Procjena genotoksičnosti bleomicina i mitomicina C metodom kometnog testa

Although chemotherapy targets cancer tissue, it also damages the DNA of non-cancer cells. The aim of this study was to evaluate the in vitro genotoxic potential of therapeutic concentrations of bleomycin and mitomycin C, added alone or in combination to cultures of human peripheral lymphocytes. The levels of DNA damage and repair were assessed using the alkaline comet assay immediately after cell treatment as well as 24 and 48 hours following treatment. The results indicate that individual drugs and their combination induce a significant DNA damage to peripheral blood lymphocytes. Bleomycin alone induced the highest levels of primary DNA damage immediately after cell treatment. Although mitomycin C alone induced massive cross-linking and retarded DNA migration in resting cells, active proliferation and repair processes significantly increased DNA damage. Combined, they showed a synergetic effect, inducing complex patterns of DNA damage in peripheral blood lymphocytes and producing different types of lesions and a number of DNA alterations that directly or indirectly increased DNA migration. Our study has confirmed the sensitivity of the alkaline comet assay for assessing bleomycin and/or mitomycin C genotoxicity to human lymphocytes at concentration levels used in clinic. It has also demonstrated the utility of the alkaline comet assay as one of the primary screening methods for in vitro studies of drug-DNA interactions, especially in studying mechanisms of action of new drugs.Većina antineoplastičnih lijekova ima nespecifično djelovanje pa su na njihovu primjenu osjetljive i stanice zdravog tkiva. U pretkliničkim istraživanjima lijekova važnu ulogu imaju brzi i osjetljivi testovi za procjenu razina oštećenja i popravka stanične DNA. Cilj istraživanja bio je procijeniti toksičke učinke bleomicina i mitomicina C na genom ljudskih limfocita u uvjetima in vitro primjenom kometnog testa u alkalnoj izvedbi. Limfociti su 24 h izlagani pojedinačnim lijekovima te njihovoj kombinaciji u terapijskim koncentracijama, a potom je praćena dinamika oštećenja i popravka DNA. Postavljena su dva pokusa: (A) u kojem su lijekovi dodavani u trenutku uspostavljanja staničnih kultura kako bi se procijenili toksički učinci na limfocite u fazi mirovanja i početnim fazama rasta, i (B) u kojem su lijekovi dodavani nakon 24 h rasta stanica u kulturi, kako bi se istražili učinci na stanice u diobi. Rezultati istraživanja pokazuju da oba lijeka izazivaju značajna primarna oštećenja limfocitne DNA. Razine oštećenja i dinamika njihova popravka ovisne su o diobenoj aktivnosti limfocita i njihovu položaju unutar staničnog ciklusa. Oštećenja izazvana bleomicinom vrlo su jaka neposredno nakon tretmana, a u kasnijim fazama rasta limfocita većinom se popravljaju. Mitomicin C izaziva drukčiji obrazac oštećenja i popravka DNA. Zbog ukriženog povezivanja između lanaca DNA, on značajno usporava migraciju DNA tijekom elektroforeze u alkalnim uvjetima, a visoke razine oštećenja koje se detektiraju u kasnijim fazama rasta uzrokovane su procesima popravka DNA. Bleomicin i mitomicin C sinergistički izazivaju opsežna oštećenja limfocitne DNA, osobito u diobeno aktivnim stanicama. Dobiveni rezultati govore u prilog primjene kometnog testa u pretkliničkim istraživanjima antineoplastičnih lijekova i upućuju na moguću primjenu ove metode u procjeni oštećenja genoma proizašlih iz izloženosti ovim agensima

Radioprotektivni učinci amifostina i melatonina na ljudske limfocite izložene gama-zračenju u uvjetima in vitro

Radioprotective effects of amifostine and melatonin as well as their ability to modulate the level of spontaneous and gamma-irradiation-induced genetic changes on human peripheral blood lymphocytes were investigated using the cytokinesis-block micronucleus (CBMN) assay and sister chromatid exchange (SCE). Parallel blood samples were pre-treated with amifostine, melatonin and their combination for 30 minutes. Negative controls were also included. After the treatment with radioprotectors, one blood sample of each experimental group was exposed to gamma-rays from a 60Co source. The radiation dose absorbed was 2 Gy. Our research confirmed the radioprotective effects of both chemicals in vitro, with no significant genotoxicity. Pre-treated irradiated blood samples showed a decrease in the total number of micronuclei (MN) and in the number of cells with more than one MN. They also showed significantly lower mean SCE values. This study shows that it is possible combine these radioprotectors by adjusting the doses of amifostine to achieve the best radioprotective effect with as few side effects as possible. However, further in vitro and clinical studies are needed to clarify their mechanisms of action and possible interactions.Primjena zračenja u liječenju zloćudnih bolesti (radioterapija) značajno pridonosi preživljenju bolesnika, ali izaziva i niz neželjenih učinaka na zdrave stanice i tkiva. Nuspojave ionizirajućeg zračenja mogu se značajno smanjiti s pomoću kemijskih spojeva s antioksidativnim učinkom koji djeluju kao ‘hvatači’ slobodnih radikala i štite vrlo osjetljivu molekulu DNA. Među spojeve s pretpostavljenim ili dokazanim radioprotektivnim učincima ubrajaju se amifostin i melatonin, koji su predmet istraživanja ovog rada. U literaturi nema dovoljno podataka o njihovoj genotoksičnosti ni međusobnim interakcijama. Stoga smo primjenom mikronukleusnog testa i analize izmjena sestrinskih kromatida (SCE) u uvjetima in vitro istražili djelovanje amifostina i melatonina na genom neozračenih i ozračenih ljudskih limfocita periferne krvi. Pojedinačno ili u kombinaciji, amifostin i melatonin dodavani su u uzorke pune krvi 30 minuta prije jednokratnog ozračivanja gama-zrakama izvora 60Co. Doza zračenja iznosila je 2 Gy, a koncentracije radioprotektora odgovaraju onima prije upotrebljavanim u kliničkoj primjeni ili u preliminarnim istraživanjima na ljudskoj populaciji. Ozračena krv kultivirana je 72 h u uvjetima in vitro prema standardnim protokolima za mikronukleusni test i test izmjena sestrinskih kromatida. Učinci amifostina i melatonina usporedo su istraživani i na kontrolnim, neozračenim uzorcima krvi. Dobiveni rezultati upućuju na značajno smanjenje ukupnog broja mikronukleusa i smanjenje udjela stanica s više od jednog mikronukleusa te sniženje ukupnog broja i raspona izmjena sestrinskih kromatida u pretretiranim uzorcima krvi. Potvrđen je vrlo dobar radioprotektivni učinak svakog spoja testiranog posebno, a ujedno je utvrđeno da oba spoja sinergistički djeluju na snižavanje razina oštećenja izazvanih u genomu limfocita pod utjecajem gama-zraka. S obzirom na to da primjenom citogenetičkih testova nije dokazana genotoksičnost navedenih radioprotektora za ljudske limfocite u uvjetima in vitro, dobiveni rezultati govore u prilog daljnjih istraživanja ovih spojeva i njima srodnih tvari u uvjetima in vivo te njihove moguće zajedničke primjene u kliničkoj praksi

PROGINS Mutation of Progesterone Receptors and Its Role in Premature Birth – An Overview

Premature ( or preterm ) birth ( birth prior 37 weeks of gestation ) is big worldwide medical and socioeconomic problem. It percentage is 8-12% of total number of births, and apart from the increased mortality of newborns, it is also cause of increased morbidity in for it. worldwide, as far as some statistical reviewes say, 15 million of babies per year are preterm born. Despite the frequency, consequences and costs of premature delivery, very little has been done for preventing it, especially for preventing early premature deliveries. Etiology of premature labor is multifactorial, and includes pathophysiology, genetics and enviromental factors. Resent scientific researches, particulary in the field of human genomics, show that genetic factors, mostly present in genome of mother, contribute up to 40% variation in delivery time. It is belived that premature birth has same cascade of events like normal birth; just in this case it starts sooner. This process is controlled by series of hormonal effects between fetus, placenta and mother. One of the key signaling pathways in this series is progesterone one. PROGINS allele is progesterone receptor gene modification. It is built of 3 variants : V660L,H770H and alu insertion. Progesterone receptors with PROGINS mutation are less susceptible to progesteron activity, and it looks as the withdrawal of progesterone causes the beggining of birth cascade. +331G/A progesterone receptor mutation is newly discovered mutation. It is belived that this mutation leads to PR-a an PR-B receptor quantity disorder before delivery term. The aim of this review is to resume all recent aknowledgements about PROGINS and +331G/A mutation of progesterone receptor and see if there is the value of these genetic mutations in modulation of risk for preterm birth

Različiti učinci samih hlapljivih anestetika ili u kombinaciji s gama-zračenjem od 1 i 2 Gy in vivo na DNA mišje jetre: preliminarno istraživanje

As the number of radiotherapy and radiology diagnostic procedures increases from year to year, so does the use of general volatile anaesthesia (VA). Although considered safe, VA exposure can cause different adverse effects and, in combination with ionising radiation (IR), can also cause synergistic effects. However, little is known about DNA damage incurred by this combination at doses applied in a single radiotherapy treatment. To learn more about it, we assessed DNA damage and repair response in the liver tissue of Swiss albino male mice following exposure to isoflurane (I), sevoflurane (S), or halothane (H) alone or in combination with 1 or 2 Gy irradiation using the comet assay. Samples were taken immediately (0 h) and 2, 6, and 24 h after exposure. Compared to control, the highest DNA damage was found in mice receiving halothane alone or in combination with 1 or 2 Gy IR treatments. Sevoflurane and isoflurane displayed protective effects against 1 Gy IR, while with 2 Gy IR the first adverse effects appeared at 24 h post-exposure. Although VA effects depend on liver metabolism, the detection of unrepaired DNA damage 24 h after combined exposure with 2 Gy IR indicates that we need to look further into the combined effects of VA and IR on genome stability and include a longer time frame than 24 h for single exposure as well as repeated exposure as a more realistic scenario in radiotherapy treatment.Kako se broj radioterapijskih i radioloških dijagnostičkih postupaka iz godine u godinu povećava, tako raste i primjena hlapljivih anestetika za opću anesteziju. Iako se smatralo sigurnim, izlaganje hlapljivim anesteticima može izazvati različite štetne učinke, a u kombinaciji s ionizirajućim zračenjem može izazvati i sinergijske učinke. Međutim, malo se zna o oštećenju DNA koje uzrokuje ova kombinacija u dozama primijenjenima u jednom izlaganju u radioterapiji. Kako bismo saznali više o tome, alkalnim komet-testom analizirali smo oštećenje DNA i odgovor na popravak u jetrenom tkivu muških Swiss albino miševa nakon izlaganja samo izofluranu, sevofluranu ili halotanu, odnosno u kombinaciji sa zračenjem od 1 ili 2 Gy. Uzorci su uzeti odmah (0 h) te 2, 6 i 24 sata nakon izlaganja. U usporedbi s kontrolom, najveća oštećenja DNA utvrđena su u miševa koji su primili halotan, sam ili u kombinaciji sa zračenjem od 1 ili 2 Gy. Sevofluran i izofluran pokazali su zaštitne učinke nakon izlaganja zračenju od 1 Gy, a pri 2 Gy prve nuspojave pojavile su se 24 sata nakon izlaganja. Iako učinci hlapljivih anestetika ovise o metabolizmu jetre, otkrivanje nepopravljenog oštećenja DNA 24 sata nakon kombinirane izloženosti sa zračenjem od 2 Gy upućuje na to da trebamo nastaviti istraživati kombinirane učinke hlapljivih anestetika i ionizirajućega zračenja na stabilnost genoma i obuhvatiti šire razdoblje nakon jednokratne izloženosti (duže od 24 sata). Također treba obuhvatiti višekratna izlaganja kao realističniji scenarij u liječenju radioterapijom

Utjecaj majčinih i fetalnih faktora na uspješnost medikamentozne indukcije poroda

Labour induction is the process in which labour is induced mechanically or pharmacologically. The percentage of induced labours is between 1.4% and 32% of the total number of births in the world. The aim of this research is to present the number of medically induced labours from 2012 to 2019 at the Clinic for Gynaecology and Obstetrics of the Clinical Hospital Center in Osijek and to present the success rate of medically induced labour and factors, both maternal and/or foetal which may affect it. Materials and methods: In the study 2361 subjects were included whose births were induced by medication regardless of the indication for medically induced labour, gestational age or mother’s age. χ2 test, Mann Whitney U test, Fisher’s exact test, Kruskal Wallis test (Pot Hoc Conover), and the univariate and multivariate logistic regression model were used. Results: The percentage of inductions was 13.8%. 81% of the child births was completed vaginally , while 19% was completed by the caesarean section. The univariate regression analysis found that meconium amniotic fluid increases the risk of the caesarean section after the labour has been induced. Factors decreasing the possibility of the caesarean section after induced labour include multiparity, women age between 25 and 35 years and women bearing female children. The multivariate statistical regression model found that women over the age of 36 are 1.58 times more likely to have the caesarean section. Women with meconium amniotic fluid are 1.47 times more likely to have the caesarean section. Multiparity in the mother and the female sex of the child reduce the probability of the caesarean section after induced labour (odds ratio (OR) 0.20, P=0.02 and OR 0.84, P=0.09, respectively). Conclusion: The study indicates that multiparity and female gender of child increase the probability of the vaginal birth after the induction, while the mother’s age over 36 and meconium amniotic fluid after the induction increase the risk of the caesarean section.Indukcija poroda postupak je kojim mehaničkim ili farmakološkim putem pokušavamo potaknuti porod. Postotak induciranih porođaja u svijetu mjeri se od 1,4 do čak 32 % od ukupnog broja poroda. Cilj je ovog preglednog rada prikazati broj medikamentozno induciranih poroda u razdoblju od 2012. do 2019. godine na Klinici za ginekologiju Kliničkog bolničkog centra u Osijeku, prikazati uspješnost medikamentozne indukcije poroda te koji od materničnih i/ili fetalnih faktora mogu utjecati na uspjeh indukcije poroda. Materijali i metode: Koristili smo podatke iz rađaonskog protokola Klinike za ginekologiju i porodništvo Kliničkog bolničkog centra u Osijeku. U istraživanje smo uključili 2361 ispitanicu čiji su porodi inducirani medikamentozno. Statistički smo obradili podatke o vrsti indukcije poroda, indikacijama za indukciju poroda te načinu poroda nakon indukcije. Koristili smo χ2 test, Mann Whitney U test, Fisherov egzaktni test, Kruskal Wallis test (Pot Hoc Conover) te model univarijantne i multivarijantne logističke regresije. Rezultati: Postotak indukcija bio je 13,8 %. U 81 % slučajeva porod je dovršen vaginalnim putem, dok je u 19 % slučajeva dovršen carskim rezom. Utvrdili smo da je čimbenik rizika za carski rez nakon indukcije poroda dijagnoza mekonijske plodove vode, dok su čimbenici koji smanjuju vjerojatnost carskog reza – dob majke od 25 do 35 godina, trudnice koje su rodile žensko dijete te trudnice koje su do sada već rađale. Modelom multivarijantne statističke regresije utvrdilo se da žene u dobi iznad 36 godina imaju 1,58 puta veću šansu za carski rez u odnosu na mlađe, a one s prisutnom dijagnozom mekonijske plodove vode 1,47 puta veću šansu za carski rez u odnosu na one koje nemaju navedenu dijagnozu. Multiparitet u majke te ženski spol djeteta smanjuju vjerojatnost carskog reza nakon indukcije poroda (redom OR 0.20, P = 0.02 te OR 0.84, P = 0.09). Zaključak: Studija je pokazala da su multiparitet i ženski spol djeteta protektivni faktori za vaginalni porod, dok su dob majke iznad 36 godina te zelena plodna voda nakon indukcije poroda rizični faktori za carski rez

Lokoregionalna terapija u liječenju hepatocelularnog karcinoma – prikaz slučaja

A hepatocellular carcinoma (HCC) is a primary liver malignancy, often arising in the setting of chronic liver disease. Incidence of this carcinoma is increasing at a great rate. Disease often manifests asymptomatically and to make the final diagnosis is often challenging. Screening of patients at risk is based on ultrasound (US) examinations, which in the setting of suspicion lesion findings often converts to multiphasic computed tomography (CT) and magnetic resonance imaging (MRI) procedures for advanced disease evaluation. The selection of treatment modality depends on tumor size and location, extrahepatic spread and subsequent liver disease. For years the first line of treatment was liver resection and transplantation. Locoregional therapy is a novel approach to diverse stages of HCC with good response and higher overall survival rates, especially in early stages. Transarterial chemoembolization (TACE) is the method of choice in patients with multifocal HCC and maintained liver function, unsuitable for surgical treatment. We present a patient with HCC in the setting of hepatitis C virus (HCV) infection, treated with combined methods of locoregional therapy.Hepatocelularni karcinom (HCC) je primarna maligna bolest jetre. Uslijed porasta broja oboljelih od kroničnog hepatitisa koji u konačnici dovodi do stadija ciroze jetre, incidencija ovog karcinoma je u porastu. U svom početnom stadiju bolest je najčešće asimptomatska, a postavljanje konačne dijagnoze je zahtjevno i s odgodom. Probir visoko rizične populacije zasniva se na ultrazvučnoj dijagnostici koja se, u slučaju pronalaska sumnjive lezije, nadopunjuje multifaznim CT i MR pregledom radi daljnje evaluacije bolesti. Odabir terapijske metode ovisi o veličini i lokaciji tumora, ekstraheptalnom širenju i priležećoj bolesti jetre. Prema svim dosadašnjim smjernicama, liječenje je uključivalo kiruršku resekciju i transplantaciju jetre. U pacijenata s određenim stadijem bolesti danas je metoda odabira lokoregionalna terapija. Tehnike ablacije pogodne su za pacijente u vrlo ranoj fazi bolesti. Transarterijska embolizacija (TACE) je metoda odabira kod pacijenata s multifokalnim HCC-om održane jetrene funkcije, nepodobnih za operaciju. Primjena lokoregionalne terapije s kombinacijom ostalih tehnika pridonosi boljoj rezoluciji bolesti s boljim ishodima preživljenja. U prikazanom slučaju, pratimo pacijenticu s HCCom u podlozi hepatitis C virusne (HCV) infekcije kod koje se, odlukom multidisciplinarnog tima, odlučilo na lokoregionalnu terapiju naizmjeničnom kombinacijom mikrovalne ablacije i TACE kod recidivirajućeg HCC-a

Utjecaj niskih doza klorpirifosa na krvne i stanice koštane srži štakora

The aim of this study was to investigate the genotoxic potential of low doses of chlorpyrifos (CPF) on blood and bone marrow cells in adult male Wistar rats. CPF was administered by oral gavage at daily doses of 0.010, 0.015, and 0.160 mg/kg of body weight (bw) for 28 consecutive days. Positive control (PC) was administered 300 mg/kg bw/day of ethyl methane sulphonate (EMS) for the final three days of the experiment. Toxic outcomes of exposure were determined with the in vivo micronucleus (MN) assay and alkaline comet assay. The 28-day exposure to the 0.015 mg/kg CPF dose, which was three times higher than the current value of acute reference dose (ARfD), reduced body weight gain in rats the most. The in vivo MN assay showed significant differences in number of reticulocytes per 1000 erythrocytes between PC and negative control (NC) and between all control groups and the groups exposed to 0.015 and 0.160 mg/kg bw/day of CPF. The number of micronucleated polychromatic erythrocytes per 2000 erythrocytes was significantly higher in the PC than the NC group or group exposed to 0.015 mg/kg bw/day of CPF. CPF treatment did not significantly increase primary DNA damage in bone marrow cells compared to the NC group. However, the damage in bone marrow cells of CPF-exposed rats was much higher than the one recorded in leukocytes, established in the previous research. Both assays proved to be successful for the assessment of CPFinduced genome instability in Wistar rats. However, the exact mechanisms of damage have to be further investigated and confirmed by other, more sensitive methods.Istražen je genotoksični potencijal niskih doza klorpirifosa na uzorcima krvi i stanica koštane srži u odraslih mužjaka štakora soja Wistar. Pokusnim je životinjama klorpirifos bio 28 dana oralno apliciran pomoću sonde u dnevnim dozama od 0,010 mg/kg t. m., 0,015 mg/kg t. m. i 0,160 mg/kg t. m. Kao pozitivna kontrola korišten je etil metan sulfonat (EMS) u dozi od 300 mg/kg t. m. tijekom posljednja tri dana pokusa. Toksični ishodi izloženosti klorpirifosu istraženi su primjenom in vivo mikronukleus (MN) testa i alkalnoga komet-testa. Utvrdili smo da je 28-dnevna izloženost klorpirifosu u dozi od 0,015 mg/kg t. m./dan, koja je trostruko viša od važeće vrijednosti akutne referentne doze, u najvećoj mjeri smanjila prirast tjelesne mase štakora. Rezultati MN-testa upućuju na značajne razlike u broju retikulocita na 1000 eritrocita između pozitivne i negativne kontrole te između obiju kontrola i skupina izloženih klorpirifosu u dnevnim dozama 0,015 i 0,160 mg/kg t. m. Broj polikromatskih eritrocita s mikronukleusima na 2000 eritrocita u pozitivnoj kontroli bio je značajno povećan u usporedbi s negativnom kontrolom te s uzorcima krvi štakora izloženih klorpirifosu u dnevnoj dozi od 0,015 mg/kg t. m. Izloženost CPF-u nije uzrokovala statistički značajan porast razine primarnih oštećenja DNA u stanicama koštane srži u usporedbi s razinama spontanih oštećenja DNA, izmjerenima alkalnim komet-testom u negativnoj kontroli. Međutim, razine oštećenja u stanicama koštane srži štakora izloženih klorpirifosu bile su značajno više od onih zabilježenih u leukocitima, koje su poznate iz prethodnih istraživanja. Oba su se testa pokazala uspješnima za procjenu nestabilnosti genoma izazvanih klorpirifosom u Wistar štakora. Međutim, točni mehanizmi oštećenja moraju se dodatno istražiti i potvrditi drugim osjetljivijim metodama

DNA Repair Gene Polymorphisms and Sensitivity to Ionising Radiation

Cilj ovog istraživanja bio je procijeniti razinu oštećenja DNA u leukocitima periferne krvi prije, neposredno nakon i 120 min nakon ozračivanja dozom zračenja od 2 Gy te usporediti razine nastalih oštećenja između kontrolne skupine i skupine medicinskih radnika izloženih niskim dozama ionizirajućeg zračenja na svojim radnim mjestima. Istražen je utjecaj polimorfi zma u genima koji sudjeluju u popravku DNA; *hOGG1, XRCC1 i MGMT na razinu izmjerenih oštećenja. Istraživanjem je obuhvaćeno 40 zdravih ispitanika obaju spolova (20 kontrola i 20 izloženih). Razina oštećenja DNA mjerena je komet-testom u alkalnim uvjetima, pri čemu su za svakog ispitanika i svaku vremensku točku analizirane vrijednosti dužine repa, % DNA u repu i repnog momenta kometa. Rezultati pokazuju da su vrijednosti % DNA u repu i repni moment kometa bili statistički značajno viši u izloženoj populaciji prije, neposredno nakon i 120 min nakon ozračivanja. Pokazano je da nosioci polimorfnih alela ovih gena u izloženoj skupini imaju statistički značajno više razine oštećenja DNA, kako naspram homozigota pripadne skupine, tako i naspram cijele kontrolne skupine te da početno oštećenje DNA značajno negativno korelira s ukupnom dozom zračenja koju su primili tijekom radnog vijeka. Dobiveni rezultati upućuju na vrijednost kombiniranja alkalnoga komet-testa i genotipizacije izloženih pojedinaca u genima za popravak DNA, što bi moglo pridonijeti prepoznavanju subpopulacija sklonijih nakupljanju oštećenja DNA, a time i sklonijih riziku od razvoja tumorskih bolesti.Increasing exposure to ionising radiation raises a great concern about potential DNA damage in occupationally exposed individuals. Polymorphisms of DNA repair genes can determine individual sensitivity and DNA damage response to low doses of ionising radiation. The objective of this study was to assess DNA damage in leukocytes at baseline, immediately after and 120 min after exposure to gamma-radiation of 2 Gy, to compare DNA damage between the control group of subjects and subjects occupationally exposed to low-dose gamma-radiation, and to determine the relationship between hOGG1 (8-oxoG specifi c DNA glycosylase/AP-Lyase, Ser326Cys), XRCC1 (X-ray repair cross-complementing protein-group 1, Arg194Trp), and MGMT(O6-methylguanine-DNA methyltransferase, Leu84Phe) gene and DNA damage. The study enrolled 40 healthy subjects (20 controls and 20 occupationally exposed subjects), whose leukocytes were exposed to ionising radiation and tested for DNA damage (tail length, percentage od DNA in comet tail, and tail moment) using the alkaline version of the comet assay. Our results show that tail DNA percentage and tail moment were signifi cantly higher in the exposed group at baseline, immediately after, and 120 min after exposure to 2 Gy. The exposed subjects carrying polymorphic alleles had signifi cantly higher DNA damage than homozygous carriers of the same gene and controls. Combined use of the alkaline comet assay and genotyping of DNA repair genes could help discover sensitive occupationally exposed individuals who can accumulate higher DNA damage and are at higher risk of developing tumours

Oštećenje DNA stanica bubrega in vivo prouzročeno kombiniranim izlaganjem hlapljivim anesteticima i radioterapijskim dozama od 1 Gy ili 2 Gy

Patient immobilisation with volatile anaesthetics (VA) during radiotherapy is sometimes unavoidable. Although it is known that both Vas and ionising radiation can have nephrotoxic effects, there are no studies of their combined effects on DNA damage. The aim of this in vivo study was to address this gap by investigating whether 48 groups of healthy Swiss albino mice (totalling 240) would differ in kidney cell DNA damage response (alkaline comet assay) to isoflurane, sevoflurane, or halothane anaesthesia and exposure to 1 Gy or 2 Gy of ionising radiation. We took kidney cortex samples after 0, 2, 6, and 24 h of exposure and measured comet parameters: tail length and tail intensity. To quantify the efficiency of the cells to repair and re-join DNA strand breaks, we also calculated cellular DNA repair index. Exposure to either VA alone increased DNA damage, which was similar between sevoflurane and isoflurane, and the highest with halothane. In combined exposure (VA and irradiation with 1 Gy) DNA damage remained at similar levels for all time points or was even lower than damage caused by radiation alone. Halothane again demonstrated the highest damage. In combined exposure with irradiation of 2 Gy sevoflurane significantly elevated tail intensity over the first three time points, which decreased and was even lower on hour 24 than in samples exposed to the corresponding radiation dose alone. This study confirmed that volatile anaesthetics are capable of damaging DNA, while combined VA and 1 Gy or 2 Gy treatment did not have a synergistic damaging effect on DNA. Further studies on the mechanisms of action are needed to determine the extent of damage in kidney cells after longer periods of observation and how efficiently the cells can recover from exposure to single and multiple doses of volatile anaesthetics and radiotherapy.Imobilizacija bolesnika hlapljivim anesteticima (HA) tijekom radioterapije ponekad je neizbježna. Iako je poznato da i HA i ionizirajuće zračenje mogu imati nefrotoksične učinke, ne postoje istraživanja o njihovu kombiniranom učinku na oštećenje DNA bubrežnih stanica. Cilj ovog istraživanja in vivo na miševima soja Swiss albino bio je utvrditi oštećenje DNA stanica bubrega (alkalni komet-test) nakon anestezije izofluranom, sevofluranom ili halotanom i izlaganja ionizirajućem zračenju u dozama od 1 Gy ili 2 Gy. Uzorke bubrežnoga korteksa uzeli smo nakon 0, 2, 6 i 24 sata od izlaganja i izmjerili parametre komet-testa: duljinu repa i njegov intenzitet. Kako bismo kvantificirali učinkovitost staničnoga popravka, izračunali smo indeks popravka stanične DNA. Izloženost bilo kojem od testiranih anestetika povećalo je oštećenje DNA u odnosu na kontrolu, slično kod sevoflurana i izoflurana, a najveće kod halotana. U kombiniranom izlaganju HA-u i zračenju od 1 Gy, oštećenje DNA ostalo je na sličnim razinama u svim vremenskim točkama, ili je bilo čak niže od oštećenja prouzročenih samim zračenjem. Halotan je ponovno izazvao najveća oštećenja. U kombiniranom izlaganju sa zračenjem od 2 Gy sevofluran je značajno povećao intenzitet repa tijekom prvih triju vremenskih točaka, koji se smanjivao te je nakon 24 sata čak bio niži nego u uzorcima koji su bili izloženi samo zračenju. Potrebna su daljnja istraživanja mehanizma djelovanja kako bi se utvrdilo u kojoj mjeri oštećenja ostaju u bubrežnim stanicama nakon duljeg razdoblja, kao i koliko se učinkovito stanice mogu oporaviti nakon jednokratnog ili višekratnog izlaganja HA-u i zračenju

Are There Differences in Students’ School Success, Biorhythm, and Daytime Sleepiness Depending on Their School Starting Times?

Chronotype is a characteristic of a person in a certain point of one’s lifetime and it slowly changes with age. Adolescents start to go to bed later while schools impose early starting hours, which may become a problem for students who are unable to adapt their circadian rhythm. The aim of this study was to determine if differences in school starting times affect the students’ chronotype, school success, or daytime sleepiness. We tested a total of 1020 students from four high schools in Osijek, Croatia. The students had alternating school shifts (school starting hours 7 AM or 13 PM and 8 AM or 14 PM, every other week, alternatively, respectively). The participants were tested using the Epworth Sleepiness Scale and the Morningness – Eveningness Questionnaire. Earlier chronotypes were characteristic of the students starting school earlier, but without significant difference in daytime sleepiness in comparison with those starting school later. Differences were also found between different age and gender groups, female and older students having earlier chronotypes. Students going to school earlier showed better school success than the latter. In conclusion, the study shows that students starting school earlier also have earlier chronotypes, which might be consequence of the adaptation to one hour earlier school starting time