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Electrochemical characterization of dimeric metallosurfactants
No full textPovršinski aktivne tvari, zahvaljujući svojim amfifilnim svojstvima, nalaze široku primjenu u različitim područjima, uključujući i elektrokemiju. U ovom radu provedena je elektrokemijska karakterizacija staklaste ugljikove elektrode (GC) u prisutnosti dimerne kationske površinski aktivne tvari (12-2-12) (PAT) te u prisutnosti PAT-a koji u protuionu sadrži različite prijelazne metale (12-2-12)[MBr4] pri čemu je M = Co, Ni, Zn, Cu (PAT M). Ispitivanja su provedena u otopini elektrolita, Na2SO4, pri koncentracijama ispod (PAT 1/PAT 1 M) i iznad (PAT 2/PAT 2 M) kritične micelizacijske koncentracije (cmc) korištenjem elektrokemijske impedancijske spektroskopije (EIS) i cikličke voltammetrije (CV). Rezultati su pokazali da dodatak PAT 1 u otopinu elektrolita ne uzrokuje značajne promjene u elektrokemijskom odzivu GC elektrode dok dodatak PAT 2 dovodi do povećanja kapaciteta elektrode. U prisutnosti PAT M spojeva (M = Co, Ni, Zn), osobito u koncentracijama iznad cmc-a (PAT 2 M), zabilježen je porast specifičnih struja i nastanak novih strujnih vrhova u CV-u GC elektrode, kao i složeniji odgovori u EIS-u (više od jedne vremenske konstante). To ukazuje na prisutnost dodatnih elektrokemijskih procesa osim čistog nabijanja/izbijanja električnog dvostrukog sloja. Najizraženiji efekti zabilježeni su u prisutnosti PAT-a koji sadrži Cu, osobito pri višoj koncentraciji (PAT 2 Cu). Voltamogrami i impedancijski spektri (IS) GC elektrode u tim slučajevima pokazuju značajne elektrokemijske promjene unutar ispitivanog sustava. One se manifestiraju kroz dodatne strujne vrhove u CV-u te kao dodatne vremenske konstante u IS-u ukazujući na postojanje brojnijih redoks procesa i kompleksniju elektrokemijsku dinamiku unutar ispitivanog sustava.Surfactants are widely used in many different areas, including electrochemistry owing to their amphiphilic properties. In this work, the electrochemical characterization of glassy carbon electrode (GC) was carried out in the presence of a dimeric surfactants (12-2-12) (PAT) and in the presence of PAT with modified transition metal counterion (12-2-12)[MBr4], i.e., M = Co, Ni, Zn, Cu (PAT M). The electrochemical behavior of GC was carried out in an electrolyte solution, Na2SO4, containing different concentrations of PAT/PAT M solutions: pre-micellar (PAT 1/PAT 1 M) and post-micellar (PAT 2/PAT 2 M). The electrochemical techniques used were electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The results showed that the addition of PAT 1 to the electrolyte solution does not lead to any significant changes in the electrochemical response of the GC electrode. On the other hand, the addition of PAT 2 leads to an increase in electrode capacity. In the presence of PAT M solutions (M = Co, Ni, Zn), an increase in the specific currents and the formation of new current peaks can easily be observed in the CV, while new time constants can be recognized in the impedance spectra (IS). This indicates that in addition to the pure charging/discharging of the electrical double layer, more complex electrochemical process are also taking place. These changes become even clearer when PAT 2 M is added to the electrolyte solution. The most pronounced effects in both CV and EIS were observed in the presence of PAT Cu, especially at post-micellar concentrations (PAT 2 Cu). In these cases, the voltamograms and IS of the GC electrode show clear electrochemical changes within the tested system. These are reflected in additional current peaks in the CVs and additional time constants in the IS, indicating additional redox processes and more complex electrochemical dynamics in the tested system
Application of TXRF-Mo and EDXRF techniques for elemental analysis of whey proteins
No full textProteini sirutke su praškasti oblik proteina dobivenih iz sirutke. Pokazuju brojne korisne učinke na ljudsko zdravlje: antikancerogeni, antioksidativni i antidijabetički učinak, kardioprotektivno i hipotenzivno djelovanje, pozitivno utječu na probavno zdravlje. Na tržištu su dostupni u obliku hidrolizata proteina sirutke, koncentrata proteina sirutke i izolata proteina sirutke. Danas su u širokoj upotrebi pogotovo u fitnes industriji te je zbog toga nužna kontrola elementarnog sastava kako bi se spriječio potencijalno negativan utjecaj na ljudsko zdravlje. Glavni cilj ovog istraživanja je odrediti sadržaj metala u različitim uzorcima proteina sirutke pomoću dvije analitičke tehnike (TXRF-Mo i EDXRF) kao i usporediti učinkovitost primijenjenih tehnika za određivanje sadržaja metala te njihova primjenjivost u kontroli kvalitete proizvoda. Uzorci su pripremljeni mikrovalnom digestijom za potrebe mjerenja TXRF-Mo dok su kod EDXRF tehnike uzorci izravno mjereni bez prethodne pripreme te je određen sadržaj sljedećih elemenata: željezo, bakar, cink, brom, rubidij i stroncij. Dobiveni rezultati pokazali su kako su obje tehnike prikladne za multielementarno određivanje metala te imaju potencijal za određivanje sadržaja broma u uzorcima. Uslijed primijenjenog načina pripreme uzoraka u ovom ispitivanju, EDXRF tehnika je ekološki prihvatljivija i više u skladu s načelima „zelene kemije“ dok je TXRF-Mo osjetljivija tehnika.Whey proteins are a powdered form of protein obtained from whey. They have numerous positive effects on human health: anti-cancer, antioxidant and anti-diabetic effects, cardioprotective and blood pressure lowering effects, positive effects on digestive health. They are available on the market in the form of whey protein hydrolysates, whey protein concentrates and whey protein isolates. Nowadays, they are widely used, especially in the fitness industry, which makes it necessary to control their elemental composition to avoid their potentially negative effects on human health. The main objective of this study is to determine the metal content in different whey protein samples using two analytical techniques (TXRF-Mo and EDXRF) and to compare the effectiveness of the techniques used to determine the metal content and their usefulness in controlling product quality. The samples for the TXRF-Mo measurements were prepared by microwave digestion, while the samples for the EDXRF technique were measured directly without prior preparation. The following elements were determined: iron, copper, zinc, bromine, rubidium and strontium. The results obtained showed that both techniques are suitable for the multi-element determination of metals and have the potential to determine the bromine content in samples. Due to the method of sample preparation used in this test, the EDXRF method proved to be more environmentally friendly and more in line with "green chemistry" principles," while TXRF-Mo is a more sensitive method
The distribution of botulinum toxin type A in the rat brain after peripheral application
No full textIako predstavlja najpotentniji otrov poznat čovječanstvu, botulinum toksin tipa A (BT-A) tijekom posljednjih 30-ak godina pronašao je svoje mjesto u terapiji različitih stanja praćenih mišićom hiperkontraktilnošću. Novija ispitivanja ukazala su na njegov antinociceptivni učinak, pri čemu kronična migrena predstavlja prvu bolnu indikaciju za koju je odobren. Osim migrene, pokazuje veliki potencijal i u terapiji različitih vrsta neuropatske boli. Uz terapijsku primjenu, postao je i neizostavni dio u suvremenoj estetskoj medicini, te jedan od globalno najpopularnijih estetskih zahvata, pri čemu je smatran kao siguran i bez ozbiljnih štetnih nuspojava. Dokazi o među-sinaptičkom transportu BT-A u vizualnom, motornom i senzornom sustavu dodatno su potvrdili hipotezu o središnjem mehanizmu djelovanja na bol, s obzirom da BT-A retroaksonalnim transportom s periferije dolazi do prve sinapse unutar leđne moždine, gdje interferira s različitim neurotransmiterskim sustavima. Stoga, postavlja se pitanje ostaje li BT-A na razini leđne moždine ili se transinaptičkim prijenosom prenosi dalje u supraspinalne regije. Cilj ovog istraživanja bilo je ispitati distribuciju BT-A unutar hipotalamusa, hipokampusa, gracilne te facijalne jezgre, nakon jednostrane periferne primjene u stražnju šapu štakora. Imunohistokemijskom metodom praćen je indirektni pokazatelj proteolitičke aktivnosti BT-A, pokidani fragment SNAP-25 proteina. Signal pokidanog SNAP-25 detektiran je unutar svih promatranih regija, pri čemu je kod skupine kojoj je primijenjen specifičan antitoksin za BT-A, uočeno smanjenje intenziteta signala. Taj učinak rezultat je neutralizacije dijela izvanstaničnog BT-A antitoksinom te indirektni dokaz među-sinaptičkog prijenosa BT-A u središnjem živčanom sustavu. Prikazani rezultati otvaraju brojna pitanja o značenju ovih nalaza, posebice u kontekstu sigurnosti dugotrajne primjene BT-A, te zahtijevaju daljnja ispitivanja.Although it represents the most potent toxin known to humanity, botulinum toxin type A (BT-A) has found its place over the last 30 years in the therapy of various conditions accompanied by muscle hypercontractility. Recent studies have indicated its antinociceptive effect, with the first case of approval as treatment for chronic migraine. Besides migraine, it shows great potential in the therapy of various types of neuropathic pain. In addition to therapeutic use, it has also become an indispensable part of modern aesthetic medicine and one of the most popular aesthetic procedures, generally being accepted as safe and without serious adverse side effects. Evidence of BT-A's trans-synaptic transport in the visual, motor, and sensory systems has further confirmed the hypothesis of a central mechanism of action on pain, given that BT-A reaches the first synapse within the spinal cord through retroaxonal transport from the periphery, where it interferes with various neurotransmitter systems. Therefore, the question arises whether BT-A remains at the spinal cord level or is transported trans-synaptically to supraspinal regions. The aim of this research was to examine the distribution of BT-A within the hypothalamus, hippocampus, gracile, and facial nuclei after unilateral peripheral administration to the hind paw of rats. The immunohistochemical method tracked an indirect indicator of BT-A proteolytic activity, the cleaved fragment of the SNAP-25 protein. The signal of cleaved SNAP-25 was detected within all observed regions, with a reduction in signal intensity noted in the group treated with a specific antitoxin for BT-A. This effect is the result of the neutralization of a part of extracellular BT-A by the antitoxin and an indirect proof of BT-A trans-synaptic transport in the central nervous system. The presented results raise numerous questions about the significance of these findings, especially in the context of the safety of long-term BT-A use, and require further investigation
Dietary intake of minerals among the student population
No full textU okviru ovog istraživanja procijenjen je nutritivni unos mineralnih elemenata (natrija, kalija, cinka, magnezija, željeza, fosfora, bakra, kalcija) među studentima 3. godine Farmaceutsko-biokemijskog fakulteta Sveučilišta u Zagrebu te su dobivene vrijednosti uspoređene s preporučenim unosom. Ispitivanjem je obuhvaćeno ukupno 382 ispitanika (98 muških i 284 ženskih) prosječne dobi 21,5 godina tijekom tri akademske godine 2020./2021., 2021./2022. i 2022./2023. Unos mikronutrijenata procijenjen je na temelju četverodnevnih dnevnika prehrane pri čemu su prikupljeni podaci analizirani uz pomoć računalnog programa Prehrana i statistički obrađeni. Rezultati su pokazali da su medijani dnevnog unosa natrija, fosfora i bakra za oba spola veći od preporučenog dok su medijani dnevnog unosa kalija, kalcija, magnezija i cinka manji od preporučenih vrijednosti za oba spola. Unos željeza je bio zadovoljavajući kod studenata, dok je nedostatan unos željeza zabilježen kod studentica. Studenti farmacije su unosili manje kalija, kalcija, magnezija, fosfora, željeza i cinka u usporedbi s podacima iz dostupne literature, dok je unos bakra bio veći. Unos natrija studenata približno je odgovarao podacima istraživanja drugih autora. Nezadovoljavajući rezultati ukazuju da je nužna dodatna edukacija studenata kako bi uveli promjene u vlastitoj prehrani s ciljem prevencije zdravstvenih problema u kasnijoj životnoj dobi. Također, kao zdravstveni radnici biti će dužni savjetovati pacijente o važnosti pravilne prehrane u svrhu održavanja zdravlja i pomoći kod bolesti.In this study, the dietary intake of minerals (sodium, potassium, zinc, magnesium, iron, phosphorus, copper, calcium) was assessed among 3rd-year students of the Faculty of Pharmacy and Biochemistry, University of Zagreb, and results were compared with the recommended values. The survey included a total of 382 students (98 male and 284 female) with an average age of 21.5 years in the three academic years 2020/2021, 2021/2022 and 2022/2023. The students kept a food diary for four days, and the collected diaries were analyzed using the Prehrana program. The obtained results were statistically analyzed. The results showed that median daily intake of sodium, phosphorus and copper was above the recommended values in both sexes, while the median daily intake of potassium, calcium, magnesium and zinc was below the recommended values, also in both sexes. Iron intake was adequate in male students, while female students were found to have inadequate iron intake. Pharmacy students consumed less potassium, calcium, magnesium, phosphorus, iron and zinc compared to data from the available literature, while copper intake was higher. The students sodium intake was similar to research data from other authors. The results indicate that additional education of students about proper nutrition is necessary in order to avoid health problems later in life. Furthermore, as healthcare professionals, they will be required to counsel their patients on the importance of healthy lifestyle with the purpose of maintaining health and helping with illness
Determination of metals in dietary supplements used for the treatment of inflammatory bowel diseases using graphite furnace technique
No full textPojavnost upalnih bolesti crijeva je sve učestalija u posljednjih nekoliko desetljeća širom svijeta, a
samim time raste i potražnja i potrošnja dodataka prehrani koji imaju blagotvorni učinak na
liječenje bolesti. Bilo da se koriste kao suportivna terapija ili primarna terapija iznimno je važno da
su takvi pripravci dobro kontrolirani i da je poznat njihov kompletan sastav kako bi se osigurala
sigurnost korisnika. Metali se dijele na esencijalne i neesencijalne. Esencijalni su neophodni za
život ljudi u dobro definiranim količinama. Svi metali su toksični u većim dozama i mogu izazvati
kronične metaboličke poremećaje u organizmu. Upravo iz tog razloga nastoji se što bolje
kontrolirati njihov sadržaj u lijekovima, dodacima prehrani i hrani. Cilj rada bio je analizirati
dodatke prehrani koji se koriste za liječenje upalnih bolesti crijeva. Analizirani dodaci prehrani
sadrže crni papar, indijski tamjanovac, justiciju i/ili kurkumu kao biljne droge, a prikupljeni su u
trgovinama zdravom hranom ili putem internet trgovine. Za određivanje sadržaja kroma,
molibdena i kositra korištena je grafitna atomska apsorpcijska spektrometrija nakon uklanjanja
složene matrice spaljivanjem uzoraka mikrovalnom digestijom. Sadržaj metala u svim
analiziranim uzorcima bio je ispod propisanih maksimalnih vrijednosti propisanim od strane
regulatornih tijela.The prevalence of inflammatory bowel diseases has been increasing globally over the past few
decades, leading to a growing demand and consumption of dietary supplements with beneficial
effects on disease treatment. Whether used as supportive or primary therapy, it is crucial that such
preparations are well-regulated and their complete composition is known to ensure user safety.
Metals are categorized into essential and non-essential. Essential metals are necessary for human
life in well-defined quantities. All metals are toxic in larger doses and can cause chronic metabolic
disorders in the body. Therefore, the content of drugs, dietary supplements, and food is strictly
controlled. The aim of this study was to analyze dietary supplements used for treating
inflammatory bowel diseases. The analyzed supplements contain black pepper, Indian
frankincense, justice, and/or turmeric as herbal drugs, and were collected from health food stores
or through online shops. Graphite atomic absorption spectrometry was used after removing the
complex matrix by microwave digestion of the samples to determine the content of chromium,
molybdenum, and tin. The metal content in all analyzed samples was below the maximum values
prescribed by regulatory bodies
Consumer acceptance of chatbots measured by the UTAUT2 model
No full textDiplomski rad fokusira se na prihvaćenost chatbotova od strane potrošača, koristeći UTAUT2 model. Predmet rada je analiza kako korisnici percipiraju i prihvaćaju chatbotove u digitalnom okruženju, a cilj je identificirati ključne faktore koji utječu na njihovu odluku o prihvaćanju ove tehnologije. S obzirom na brzinu razvoja tehnologije i njezin sveprisutni utjecaj na svakodnevni život i poslovne procese, razumijevanje načina na koji korisnici reagiraju na inovacije i umjetnu inteligenciju postaje ključno. Istraživanje prihvaćenosti tehnologije omogućuje nam da prepoznamo prepreke i poticaje koji utječu na usvajanje novih rješenja, čime se može poboljšati razvoj i implementacija tehnologija te povećati njihova efikasnost i korisnost za korisnike. U okviru istraživanja, provedena je anketa među 126 ispitanika, pri čemu su analizirane demografske karakteristike, iskustvo i prihvaćenost chatbotova. Rezultati pokazuju da je 70,6% ispitanika koristilo chatbotove, s najvećom popularnošću chatbotova na web stranicama tvrtki i u mobilnim aplikacijama. Istraživanje je otkrilo umjerenu percepciju koristi od chatbotova, visoku ocjenu jednostavnosti njihove upotrebe, te umjerenu zabrinutost za privatnost i sigurnost informacija. Ovi nalazi pružaju uvid u složene odnose između korisnika i tehnologije te ističu važnost razumijevanja faktora koji oblikuju prihvaćenost novih tehnologija.The thesis focuses on consumer acceptance of chatbots, using the UTAUT2 model. The subject of the thesis is the analysis of how users perceive and accept chatbots in the digital environment, with the goal of identifying key factors influencing their decision to adopt this technology. Given the rapid pace of technological development and its pervasive impact on daily life and business processes, understanding how users react to innovations and artificial intelligence is crucial. Research into technology acceptance helps identify barriers and incentives affecting the adoption of new solutions, thereby improving the development and implementation of technologies and enhancing their effectiveness and utility for users. The study involved a survey of 126 participants, analyzing demographic characteristics, experience, and acceptance of chatbots. The results indicate that 70.6% of respondents have used chatbots, with the highest popularity found among chatbots on company websites and in mobile applications. The research revealed a moderate perception of the benefits of chatbots, high ratings for their ease of use, and moderate concern for privacy and information security. These findings provide insight into the complex relationship between users and technology and highlight the importance of understanding the factors that shape the acceptance of new technologies
The impact of the cosmetics industry on today's beauty standards
No full textLjudsko lice ima značajan utjecaj na kvalitetu života, stavove i mentalno stanje pojedinca, te je njihov društveni život i
mentalno stanje izravno povezan s njihovim vanjskim izgledom. Nedavni naglasak na platformskoj komunikaciji i dijeljenju
slika povećao je interes za idealizirani fizički izgled, što je rezultiralo opsesivnom borbom za ljepotom. Privlačnost lica utječe
na samopouzdanje, odabir partnera te nudi prednosti u radnom i društvenom okruženju. Estetski ideali evoluirali su kroz
povijest, a mediji danas igraju ključnu ulogu u oblikovanju tih standarda. Društvo promiče kulturu mladosti, dok starenje
postaje sveprisutnije, što dovodi do nejednakosti između idealiziranih standarda i stvarnosti. Kozmetička industrija igra važnu
ulogu u definiranju i ispunjavanju standarda ljepote, ali istovremeno može pojačati stigmu povezanu s kožnim poremećajima,
što utječe na samopoštovanje i društvenu interakciju pojedinaca. Kozmetička industrija ima znatne mogućnosti u terapiji akni
vulgaris, pri čemu se ističu sastojci poput topikalnih retinoida, salicilne kiseline, niacinamida, α-hidroksi kiselina i benzoil
peroksida. Sastojci poput pčelinjeg otrova, probiotika, prebiotika i bakuchiola također pokazuju obećanje u borbi protiv akni.
Što se tiče rosacee, kozmetička industrija nema mnogo opcija za liječenje, ali su neki sastojci poput azelaične kiseline i Centella
asiatica pokazali određene koristi. Unatoč tome, fokus je na ublažavanju crvenila i smirivanju kože, iako to ne rješava samu
srž problema. Hiperpigmentacijski poremećaji su teški za rješavanje, a najbolje opcije tretmana uključuju N-acetil glukozamin,
niacinamid, retinoide i glikolnu kiselinu. UV izloženost igra ključnu ulogu u hiperpigmentaciji, pa je važno naglasiti važnost
korištenja proizvoda s faktorom zaštite od sunca. Kada je riječ o zreloj koži, kozmetička industrija ima širok raspon sastojaka
koji se koriste za ublažavanje znakova starenja, uključujući retinoide, vitamin C, peptide, nikotinamid, feruličnu kiselinu,
koenzim Q10, zeleni čaj, egzosome i antioksidanse. Iako kozmetička industrija pruža određene mogućnosti za rješavanje
različitih kožnih problema, postoje i ograničenja, posebno kada je riječ o složenijim stanjima poput rosacee i
hiperpigmentacije. Ipak, budućnost kozmetičke industrije obećava dinamičan razvoj usmjeren na ispunjavanje sve složenijih
standarda ljepote, uključujući personalizaciju proizvoda, upotrebu održivih praksi i transparentnost u vezi sa sastojcima.
Inovacije u znanstvenim istraživanjima dovest će do razvoja novih i učinkovitijih sastojaka za njegu kože, dok će digitalna
transformacija omogućiti potrošačima bolji pristup proizvodima i informacijama o njimaThe human face has a significant impact on quality of life, attitudes, and mental state of individuals, and their social life and
mental state are directly linked to their external appearance. The recent emphasis on platform communication and image
sharing has increased interest in an idealized physical appearance, resulting in an obsessive pursuit of beauty. Facial
attractiveness affects self-confidence, partner selection, and offers advantages in work and social environments. Aesthetic
ideals have evolved throughout history, and the media today plays a key role in shaping these standards. Society promotes a
culture of youthfulness, while aging becomes more prevalent, leading to a disparity between idealized standards and reality.
The cosmetic industry plays an important role in defining and fulfilling beauty standards, but at the same time, it can exacerbate
the stigma associated with skin disorders, affecting individuals' self-esteem and social interaction. The cosmetic industry has
significant potential in the therapy of acne vulgaris, with ingredients such as topical retinoids, salicylic acid, niacinamide, αhydroxy acids, and benzoyl peroxide being highlighted. Ingredients such as bee venom, probiotics, prebiotics, and bakuchiol
also show promise in the fight against acne. Regarding rosacea, the cosmetic industry does not have many treatment options,
but some ingredients such as azelaic acid and Centella asiatica have shown certain benefits. Nevertheless, the focus is on
reducing redness and calming the skin, although this does not address the root cause of the problem. Hyperpigmentation
disorders are difficult to treat, and the best treatment options include N-acetyl glucosamine, niacinamide, retinoids, and glycolic
acid. UV exposure plays a crucial role in hyperpigmentation, so it is important to emphasize the importance of using products
with sun protection factor. When it comes to mature skin, the cosmetic industry has a wide range of ingredients used to alleviate
signs of aging, including retinoids, vitamin C, peptides, niacinamide, ferulic acid, coenzyme Q10, green tea, exosomes, and
antioxidants. Although the cosmetic industry provides some opportunities to address various skin problems, there are
limitations, especially when it comes to more complex conditions such as rosacea and hyperpigmentation. However, the future
of the cosmetic industry promises dynamic development aimed at meeting increasingly complex beauty standards, including
product personalization, the use of sustainable practices, and transparency regarding ingredients. Innovations in scientific
research will lead to the development of new and more effective skincare ingredients, while digital transformation will enable
consumers to have better access to products and information about them
Vimentin expression in nefrotoxic epithelial-mesenchymal transition caused by cysplatine in Wistar rat
No full textCisplatina je jedan od najčešćih kemoterapeutika u liječenju solidnih tumora.Vezanje cisplatine za DNA uzrokuje smrt neoplazmi, dok je nefrotoksičnost glavna negativna strana terapije. U štakorskom modelu nefrotoksičnosti cisplatine dolazi do oštećenja ravnog dijela proksimalnog kanalića (PK). Epitelno-mezenhimalna tranzicija (EMT) se očituje jedinstvenim molekulskim i morfološkim promjenama, pri čemu stanice mijenjaju ekspresiju proteina, gube polarnost, diferenciranost i funkciju epitelne barijere. Prethodno uočene promjene citoskeleta aktina i tubulina u epitelnim stanicama PK uz promjenu ekspresije intermedijarnog proteina vimentina ukazale bi da li se u nefrotoksičnosti cisplatine zbiva EMT. Korišteni su arhivski uzorci modela nefrotoksičnosti nakon jednokratne obrade cisplatinom (i.p. u dozi 5 mg/kg) mužjaka štakora soja Wistar. Najizraženiji učinak toksičnosti javlja se 5. dan nakon tretmana, a pratio se i vremenski tijek u kojem EMT nastaje. Praćenje raspodjele vimentina rađeno je imunofluorescencijski na tkivnim rezovima. Prisutnosti vimentina praćena je u homogenatima tkiva bubrega analizom western blot, dok se promjena u ekspresiji glasničke RNA pratila end- point RT-PCR tehnikom. Pojava ekspresije vimentina uočena je kroz vremenski tijek (3. dan) u tkivnim rezovima te je nađena promjena u prisutnosti proteina u homogenatima tkiva 5. dan. Nefrotoksičnost cisplatine još nije u potpunosti razjašnjena, a naši rezultati pokazuju uključenost EMT koja može objasniti gubitak funkcije bubrega i uputiti na mehanizme obrane od sekundarnih tumora i nefrotoksičnosti kod pacijenata tretiranih cisplatinom.In the treatment of solid tumors, one of the most common chemotherapeutic agents is cisplatin. The binding of cisplatin to DNA causes the death of neoplasms, while nephrotoxicity is the main downside of this therapy. In a rat model of cisplatin nephrotoxicity, damage even part of the proximal tubule (PK) occurs. Epithelial-mesenchymal transition (EMT) manifests itself through unique molecular and morphological changes, wherein cells undergo alterations in protein expression, lose polarity, differentiation, and epithelial barrier function. Previously observed cytoskeletal changes in actin and tubulin in PK epithelial cells, along with a change in the expression of intermediate protein vimentin, would indicate whether EMT occurs in cisplatin nephrotoxicity. Archival nephrotoxicity model samples were used after a single treatment with cisplatin (i.p. at a dose of 5 mg/kg) in male Wistar rats. The most pronounced toxicity effect occurs on the 5th day after treatment, during which the time course of EMT was also monitored. Vimentin distribution was observed through immunofluorescence on tissue sections. The presence of vimentin was monitored in the homogenates of kidney tissue by western blot analysis, while changes in the expression of messenger RNA were monitored using endpoint RT-PCR technique. The appearance of vimentin expression was observed over time (day 3) in tissue sections, and a change in the presence of proteins in tissue homogenates was found on day 5. The nephrotoxicity of cisplatin has not yet been fully elucidated, and our results indicate an involvement of EMT that can explain the loss of kidney function, pointing to defense mechanisms against secondary tumors and nephrotoxicity in patients treated with cisplatin
Synthesis of new aromatic C-nitroso derivatives and their adsorption on gold surface
No full textU ovom radu provedena je detaljna optimizacija sintetskih postupaka za pripravu novih aromatskih C-nitrozo derivata, koji sadrže funkcijsku skupinu sa sumporom koja im omogućuje adsorpciju na površinu zlata. U nekoliko reakcijskih koraka uspješno su sintetizirani i okarakterizirani bis(4-nitrozobenzil)disulfid i 1,2-bis(4-nitrozobifenil)disulfid. Aromatski C- nitrozo produkti su u posljednjem koraku sinteze pripravljeni redukcijom odgovarajućeg nitro derivata do N-hidroksilamina, koji je potom bez izolacije oksidiran do nitrozo spoja. Provedena su preliminarna istraživanja morfoloških i topografskih karakteristika molekularnih slojeva sintetiziranih aromatskih C-nitrozo derivata na površini zlata(111) uz pomoć mikroskopije atomskih sila. Dobiveni rezultati ukazuju na utjecaj specifičnih strukturnih karakteristika adsorbiranih nitrozo spojeva na njihovo samoudruživanje i dimerizaciju ili polimerizaciju na površini zlata.In this thesis, synthetic procedures for preparation of new aromatic C-nitroso derivatives containing a sulfur functional group for the adsorption on gold surface, were optimized in detail. In several reaction steps, bis(4-nitrosobenzyl)disulfide and 1,2-bis(4-nitrosobiphenyl)disulfide were successfully synthesized and characterized. The aromatic C-nitroso products were prepared in the final step of synthesis pathway by reducing the corresponding nitro derivative to N-hydroxylamine, which was then oxidized to the nitroso compound without isolation. Preliminary investigations of the morphological and topographical characteristics of molecular layers of synthesized aromatic C-nitroso derivatives on gold(111) surface were conducted using atomic force microscopy. The obtained results indicate the influence of specific structural characteristics of adsorbed nitroso compounds on their self-assembly and dimerization or polymerization on the gold surface
Gamma-radiolytic degradation of nabumetone in water
No full textNabumeton je jedan od nesteroidnih lipofilnih protuupalnih lijekova. Farmakološko djelovanje ostvaruje putem metabolita 6-metoksi-2-naftiloctene kiseline, koji je inhibitor enzima ciklooksigenaze. Međudjelovanjem ionizirajućeg zračenja i tvari nastaju reaktivne kratkoživuće čestice, oksidirajuće i reducirajuće vrste, koje neselektivnim reakcijama reagiraju s farmaceuticima te ih mogu prevesti u za okoliš neškodljive produkte. U sklopu ovog diplomskog rada, za kvantitativno određivanje nabumetona korištena je tekućinska kromatografija visoke djelotvornosti i UV/Vis spektrofotometrija. Djelotvornost razgradnje praćena je u vodenim otopinama pri različitim koncentracijama nabumetona, različitim dozama zračenja te različitim vrijednostima pH. Također, praćen je i utjecaj različitih "hvatača" radikala, anorganskih iona te otapala. Spregnuti sustav tekućinske kromatografije ultravisoke djelotvornosti i spektrometrije masa visokog razlučivanja korišten je za analizu razgradnih produkata nabumetona. Na temelju rezultata analize tandemnom spektrometrijom masa, pretpostavljene su strukture i sheme fragmentacije razgradnih produkata nabumetona.Nabumetone is one of the non-steroidal anti-inflammatory drugs, characterized by its non-acidic and lipophilic properties. Its pharmacological effects are achieved through the metabolite 6-methoxy-2-naphthylacetic acid, which is an inhibitor of the cyclooxygenase enzyme. Interaction of ionizing radiation and the substance results in the formation of reactive short- lived particles, oxidizing and reducing species, which, through non-selective reactions, react with pharmaceuticals and can transform them into environmentally benign products. In this work, high performance liquid chromatography and UV/Vis spectrophotometry were used for the quantification of nabumetone. The degradation efficiency was monitored in aqueous solutions at different initial concentrations of nabumetone, different radiation doses, and different pH values. Additionally, the impact of various radical scavengers, inorganic ions, and solvents was observed. A coupled system of ultra-high-performance liquid chromatography and high-resolution mass spectrometry was used for the analysis of nabumetone degradation products. Based on the results of tandem mass spectrometry analysis, structures and fragmentation schemes of nabumetone degradants were proposed