natgillin/translations-raw huggingface dataset:
N-Methyl-N′-nitro-N-nitrosoguanidine (CAS RN: 70-25-7) for stomach, duodenum or jejunum
Celice „hedgehog“ (ali „ježi“, oblaki, fantomske celice) so celice, ki kažejo mikroskopsko sliko, na kateri so majhna glava majhna (ali pa je ni) in veliki, razpršeni repi, ter ki se obravnavajo kot močno poškodovane celice, čeprav je etiologija „ježev“ negotova (glej Dodatek 3).
1,2-Dimethylhydrazine 2HCl (CAS RN 306-37-6) for liver and intestine
Zaradi njihovega videza so meritve odstotka DNK v repu z analizo slike nezanesljive, zato je treba močno poškodovane celice oceniti ločeno.
N-methyl-N-nitrosourea (CAS RN 684-93-5) for liver, bone marrow, blood, kidney, stomach, jejunum, and brain.
Pojavljanje močno poškodovanih celic je treba zabeležiti in ga navesti v poročilu, kakršno koli pomembno povečanje, za katero se predvideva, da ga je povzročila preskusna kemikalija, pa je treba previdno raziskati in razložiti.
A group of negative control animals, treated with vehicle alone, and otherwise treated in the same way as the treatment groups, should be included with each test for every sampling time and tissue.
K takemu obravnavanju lahko pripomore poznavanje morebitnega načina delovanja preskusnih kemikalij.
The % tail DNA in negative control animals should be within the pre-established laboratory background range for each individual tissue and sampling time for that species (see paragraph 16).
Preskusna enota je žival, zato je treba podatke o posamezni živali in povzete rezultate predstaviti v obliki preglednice.
In the absence of historical or published control data showing that no deleterious or genotoxic effects are induced by the chosen vehicle, by the number of administrations or by the route of administration, initial studies should be performed prior to conducting the full study, in order to establish acceptability of the vehicle control.
Zaradi hierarhične narave podatkov je priporočeno, da se določi mediana odstotka DNK v repu za vsak preparat in izračuna srednja vrednost median za vsako žival (12).
Number and Sex of Animals
Nato se določi srednja vrednost srednjih vrednosti za posamezne živali, da se dobi skupinska srednja vrednost.
Although there is little data on female animals from which to make comparison between sexes in relation to the comet assay, in general, other in vivo genotoxicity responses are similar between male and female animals and therefore most studies could be performed in either sex.
Vse te vrednosti morajo biti vključene v poročilo.
Data demonstrating relevant differences between males and females (e.g. differences in systemic toxicity, metabolism, bioavailability, etc. including e.g. in a range-finding study) encourage the use of both sexes.
Uporabijo se lahko drugi pristopi (glej odstavek 53), če so znanstveno in statistično utemeljeni.
In this case, it may be appropriate to perform a study in both sexes e.g. as part of a repeated dose toxicity study.
Statistična analiza se lahko izvede z različnimi pristopi (58) (59) (60) (61).
Group sizes at study initiation (and during establishment of proficiency) should be established with the aim of providing a minimum of 5 analysable animals of one sex, or of each sex if both are used, per group (less in the concurrent positive control group — see paragraph 29).
Pri izbiri statističnih metod, ki bodo uporabljene, je treba obravnavati potrebo po pretvorbi (npr. logaritemski ali s kvadratnim koren) podatkov in/ali prištevanje majhnega števila (npr. 0,001) k vsem vrednostim (tudi tistim, ki niso ničelne), da se zmanjšajo učinki ničelnih vrednosti celic, kot je opisano v že navedenih virih.
As a guide to maximum typical animal requirements, a study conducted according the parameters established in paragraph 33 with three dose groups and concurrent negative and positive controls (each group composed of five animals of a single sex) would require between 25 and 35 animals.
Podrobnosti analize interakcije tretiranji in spolom, kadar se uporabita oba spola, in posledična analiza podatkov, pri kateri so ugotovljene razlike ali ne, so opisane v Dodatku 2.
TREATMENT SCHEDULE
V poročilu je treba navesti tudi podatke o toksičnosti in kliničnih znakih.
Animals should be given daily treatments over a duration of 2 or more days (i.e. two or more treatments at approximately 24 hour intervals), and samples should be collected once at 2-6 h (or at the Tmax) after the last treatment (12).
a. podatki o sočasni negativni kontroli se štejejo kot sprejemljivi za vključitev v zbirko podatkov laboratorija o negativnih kontrolah iz preteklih preskusov, kot je opisano v odstavku 16;
Samples from extended dose regimens (e.g. 28-day daily dosing) are acceptable.
b. sočasne pozitivne kontrole (glej odstavek 29) morajo povzročiti odzive, skladne z odzivi iz zbirke podatkov o pozitivnih kontrolah iz preteklih preskusov, in statistično značilno povečanje v primerjavi s sočasno negativno kontrolo;
Successful combination of the comet and the erythrocyte micronucleus test has been demonstrated (10) (19).
c. analizirano je bilo ustrezno število celic in odmerkov (odstavki 52 in 36–38);
However careful consideration should be given to the logistics involved in tissue sampling for comet analysis alongside the requirements of tissue sampling for other types of toxicological assessments.
d. merila za izbor najvišjega odmerka so skladna z merili, opisanimi v odstavku 36.
Harvest 24 hours after the last dose, which is typical of a general toxicity study, is not appropriate in most cases (see paragraph 40 on sampling time).
Pod pogojem, da so izpolnjena vsa merila za sprejemljivost, se preskusna kemikalija šteje za jasno pozitivno, če:
The use of other treatment and sampling schedules should be justified (see Appendix 3).
a. se vsaj pri enem od preskusnih odmerkov pokaže statistično značilno povečanje v primerjavi s sočasno negativno kontrolo;
For example single treatment with multiple sampling could be used however, it should be noted that more animals will be required for a study with a single administration study because of the need for multiple sampling times, but on occasions this may be preferable, e.g. when the test chemical induces excessive toxicity following repeated administrations.
c. je kateri koli od rezultatov zunaj porazdelitve podatkov o negativnih kontrolah iz preteklih preskusov za dano vrsto, vehikel, način dajanja, tkivo in število odmerkov.
Whatever way the test is performed, it is acceptable as long as the test chemical gives a positive response or, for a negative study, as long as direct or indirect evidence supportive of exposure of, or toxicity to, the target tissue(s) has been demonstrated or if the limit dose is achieved (see paragraph 36).
Ko so izpolnjena vsa ta merila, se nato šteje, da lahko preskusna kemikalija povzroči prelome verig DNK v tkivih, preiskovanih s tem preskusnim sistemom.
Test chemicals also may be administered as a split dose, i.e., two treatments on the same day separated by no more than 2-3 hours, to facilitate administering a large volume.
Če je izpolnjeno samo eno od teh meril ali dva, glej odstavek 62.
Under these circumstances, the sampling time should be scheduled based on the time of the last dosing (see paragraph 40).
Pod pogojem, da so izpolnjena vsa merila za sprejemljivost, se preskusna kemikalija šteje za jasno negativno, če:
Dose Levels
b. se ne pojavi povečanje, povezano s koncentracijo, kadar se ocenjuje z ustreznim trendnostnim testom;
If a preliminary range-finding study is performed because there are no suitable data available from other relevant studies to aid in dose selection, it should be performed in the same laboratory, using the same species, strain, sex, and treatment regimen to be used in the main study according to current approaches for conducting dose range-finding studies.
c. so vsi rezultati znotraj porazdelitve podatkov o negativnih kontrolah iz preteklih preskusov za dano vrsto, vehikel, način dajanja, tkivo in število odmerkov;
The study should aim to identify the maximum tolerated dose (MTD), defined as the dose inducing slight toxic effects relative to the duration of the study period (for example, clear clinical signs such as abnormal behaviour or reactions, minor body weight depression or target tissue cytotoxicity), but not death or evidence of pain, suffering or distress necessitating euthanasia.
d. so pridobljeni neposredni ali posredni dokazi o izpostavljenosti ciljnih tkiv ali toksičnosti za ta tkiva.
For a non-toxic test chemical, with an administration period of 14 days or more, the maximum (limit) dose is 1000 mg/kg bodyweight/day.
Za preskusno kemikalijo se nato šteje, da ne more povzročiti prelomov verig DNK v tkivih, preiskovanih s tem preskusnim sistemom.
For administration periods of less than 14 days the maximum (limit) dose is 2000 mg/kg bodyweight/day.
V primerih, ko odziv ni jasno negativen ali pozitiven (tj. niso izpolnjena vsa merila, navedena v odstavku 59 oziroma 60), in za pomoč pri opredelitvi biološke pomembnosti rezultata, je treba podatke oceniti s strokovno presojo in/ali izvesti nadaljnje preiskave, če je to znanstveno utemeljeno.
For certain types of test chemicals (e.g. human pharmaceuticals) covered by specific regulations these limits may vary.
Uporabno bi lahko bilo ocenjevanje dodatnih celic (kadar je to ustrezno) ali izvajanje ponovitve preskusa, po možnosti z uporabo optimiziranih preskusnih pogojev (npr. razmik med odmerki, drugi načini dajanja, drugi časi vzorčenj ali druga tkiva).
Chemicals that exhibit saturation of toxicokinetic properties, or induce detoxification processes that may lead to a decrease in exposure after long-term administration, may be exceptions to the dose-setting criteria and should be evaluated on a case-by-case basis.
Zbirka podatkov v redkih primerih celo po izvedbi nadaljnjih preiskav onemogoča sprejetje sklepa o pozitivnih ali negativnih rezultatih, zato se zaključi, da je dvoumna.
For both acute and sub-acute versions of the comet assay, in addition to the maximum dose (MTD, maximum feasible dose, maximum exposure or limit dose) a descending sequence of at least two additional appropriately spaced dose levels (preferably separated by less than √10) should be selected for each sampling time to demonstrate dose-related responses.
Za oceno biološke pomembnosti pozitivnega ali dvoumnega rezultata so zahtevane informacije o citotoksičnosti ciljnega tkiva (glej odstavka 54 in 55).
However, the dose levels used should also preferably cover a range from the maximum to one producing little or no toxicity.
Če so pozitivne ali dvoumne ugotovitve opažene samo takrat, ko obstaja jasen dokaz o citotoksičnosti, se za študijo zaključi, da je dvoumna za genotoksičnost, razen če ni na voljo dovolj informacij, ki omogočajo dokončen sklep.
When target tissue toxicity is observed at all dose levels tested, further study at non-toxic doses is advisable (see paragraphs 54-55).
Kadar se v primerih negativnega rezultata študije opazijo znaki toksičnosti pri vseh preskušenih velikostih odmerkov, je morda priporočena nadaljnja študija z netoksičnimi odmerki.
Studies intending to more fully investigate the shape of the dose-response curve may require additional dose group(s).
vir, številka serije, če je na voljo;
Administration of Doses
stabilnost preskusne kemikalije, rok uporabe ali datum za ponovno analizo, če je znan.
In any case the route should be chosen to ensure adequate exposure of the target tissue(s).
Topilo/vehikel:
Intraperitoneal injection is generally not recommended since it is not a typical relevant route of human exposure, and should only be used with specific justification (e.g. some positive control substances, for investigative purposes, or for some drugs that are administered by the intraperitoneal route).
utemeljitev izbire topila/vehikla;
The volume should not exceed 1 ml/100 g body weight, except in the case of aqueous solutions where 2 ml/100g body weight may be used.
priprava formulacij odmerkov;
The use of volumes greater than this (if permitted by animal welfare legislation) should be justified.
analitsko določanje sestave (npr. stabilnost, homogenost, nominalne koncentracije).
Wherever possible different dose levels should be achieved by adjusting the concentration of the dosing formulation to ensure a constant volume in relation to body weight at all dose levels.
uporabljena vrsta/sev ter znanstvena in etična utemeljitev izbire;
Sampling Time
izvor, nastanitveni pogoji, prehrana, obogatitev okolja itd.;
The sampling time is a critical variable because it is determined by the period needed for the test chemicals to reach maximum concentration in the target tissue and for DNA strand breaks to be induced but before those breaks are removed, repaired or lead to cell death.
teža posameznih živali ob začetku in koncu preskusa, vključno z razponom, srednjo vrednostjo in standardnim odklonom telesne teže za vsako skupino.
The persistence of some of the lesions that lead to the DNA strand breaks detected by the comet assay may be very short, at least for some chemicals tested in vitro (52) (53).
podatki iz študije za določanje območja (če je bila izvedena);
Accordingly, if such transient DNA lesions are suspected, measures should be taken to mitigate their loss by ensuring that tissues are sampled sufficiently early, possibly earlier than the default times given below.
utemeljitev načina dajanja;
The optimum sampling time(s) may be chemical- or route-specific resulting in, for example, rapid tissue exposure with intravenous administration or inhalation exposure.
mesto injiciranja (za subkutane ali intravenske študije);
Accordingly, where available, sampling times should be determined from kinetic data (e.g. the time (Tmax) at which the peak plasma or tissue concentration (Cmax) is achieved, or at the steady state for multiple administrations).
metode za pripravo vzorca, kadar so na voljo, histopatološke analize, zlasti za kemikalijo s pozitivnim kometnim odzivom;
In the absence of kinetic data a suitable compromise for the measurement of genotoxicity is to sample at 2-6 h after the last treatment for two or more treatments, or at both 2-6 and 16-26 h after a single administration, although care should be taken to necropsy all animals at the same time after the last (or only) dose.
utemeljitev izbire tkiva;
Information on the appearance of toxic effects in target organs (if available) may also be used to select appropriate sampling times.
metode za preverjanje, ali je preskusna kemikalija dosegla ciljno tkivo ali krvni obtok, v primeru negativnih rezultatov;
General clinical observations related to the health of the animals should be made and recorded at least once a day preferably at the same time(s) each day and considering the peak period of anticipated effects after dosing (54).
podrobnosti o kakovosti hrane in vode;
At least twice daily, all animals should be observed for morbidity and mortality.
podroben opis časovnih razporedov tretiranja in vzorčenja ter utemeljitev izbir (npr. toksikokinetični podatki, če so na voljo);
For longer duration studies, all animals should be weighed at least once a week, and at completion of the test period.
metoda za blažitev bolečin, analgezija;
Food consumption should be measured at each change of food and at least weekly.
postopki za izolacijo in hrambo tkiv;
Animals exhibiting non-lethal indicators of excessive toxicity should be euthanized prior to completion of the test period, and are generally not used for comet analysis.
metode za pripravo suspenzije s posameznimi celicami/jedri;
Tissue Collection
izvor in številka serij za vse reagente (kadar je to mogoče);
Since it is possible to study induction of DNA strand breaks (comets) in virtually any tissue, the rationale for selection of tissue(s) to be collected should be clearly defined and based upon the reason for conducting the study together with any existing ADME, genotoxicity, carcinogenicity or other toxicity data for the test chemicals under investigation.
metode za vrednotenje citotoksičnosti;
Important factors for consideration should include the route of administration (based on likely human exposure route(s)), the predicted tissue distribution and absorption, the role of metabolism and the possible mechanism of action of the test chemicals.
pogoji elektroforeze;
The liver has been the tissue most frequently studied and for which there are the most data.
splošna klinična opazovanja, če obstajajo, pred in med preskusnim obdobjem za vsako žival;
Therefore, in the absence of any background information, and if no specific tissues of interest are identified, sampling the liver would be justified as this is a primary site of xenobiotic metabolism and is often highly exposed to both parent substance(s) and metabolite(s).
dokazi citotoksičnosti, če so bili pridobljeni;
In some cases, examination of a site of direct contact (for example, for orally-administered chemicals the glandular stomach or duodenum/jejunum, or for inhaled chemicals the lungs) may be most relevant.
pri študijah, ki trajajo dlje kot en teden: teža posameznih živali med študijo, vključno z območjem, srednjo vrednostjo in standardnim odklonom telesne teže za vsako skupino; poraba hrane;
Additional or alternative tissues should be selected based on the specific reasons for the test is being conducted but it may be useful to examine multiple tissues in the same animals providing the laboratory has demonstrated proficiency with those tissues and competency in handling multiple tissues at the same time.
razmerje med odzivom in odmerkom, če je očitno;
Preparation of specimens
za vsako tkivo/žival odstotek DNK v repu (ali druga merila, če so bila izbrana) in vrednosti mediane na preparat, srednje vrednosti na žival in srednje vrednosti na skupino;
For the processes described in the following paragraphs (44-49) it is important that all solutions or stable suspensions should be used within their expiration date, or should be freshly prepared if needed.
podatki o sočasni negativni kontroli in negativnih kontrolah iz preteklih preskusov z območji, srednjimi vrednostmi/medianami in standardnimi odkloni za vsako ocenjeno tkivo;
Also in the following paragraphs, the times taken to (i) remove each tissue after necropsy, (ii) process each tissue into cell/nuclei suspensions, and (iii) process the suspension and prepare the slides are all considered critical variables (see Definitions, Appendix 1), and acceptable lengths of time for each of these steps should have been determined during establishment of the method and demonstration of proficiency.
podatki o sočasni pozitivni kontroli in pozitivnih kontrolah iz preteklih preskusov;
Animals will be euthanised, consistent with effective animal welfare legislation and 3Rs principles, at the appropriate time(s) after the last treatment with a test chemical.
za tkiva, ki niso jetra, krivulja odziva na odmerek z uporabo pozitivne kontrole.
Selected tissue(s) is removed, dissected, and a portion is collected for the comet assay, whilst at the same time a section from the same part of the tissue should be cut and placed in formaldehyde solution or appropriate fixative for possible histopathology analysis (see paragraph 55) according to standard methods (12).
Ta lahko temelji na podatkih, zbranih med dokazovanjem usposobljenosti (glej odstavka 16 in 17), zajemati pa mora tudi utemeljitev s sklicevanjem na najnovejše vire v zvezi s primernostjo stopnje in razpršenostjo odzivov na kontrole za to tkivo;
The tissue for the comet assay is placed into mincing buffer, rinsed sufficiently with cold mincing buffer to remove residual blood, and stored in ice-cold mincing buffer until processed.
uporabljene statistične analize in metode, merila za obravnavanje odziva kot pozitivnega, negativnega ali dvoumnega;
In situ perfusion may also be performed, e.g. for liver, kidney.
pogostost celic „hedgehog“ v vsaki skupini in na žival.
Many published methods exist for cell/nuclei isolation.
122/1, str. 86–94.
These include mincing of tissues such as liver and kidney, scraping mucosal surfaces in the case of the gastro-intestinal tract, homogenization and enzymic digestion.
Poglavje B.8 te priloge: Subakutna strupenost pri vdihavanju: 28-dnevna študija.
The JaCVAM validation trial only studied isolated cells, and therefore in terms of establishing the method and being able to refer to the JaCVAM trial data for demonstration of proficiency, isolated cells are preferred.
Poglavje B.29 te priloge: Subkronična strupenost pri vdihavanju: 90-dnevna študija.
However, it has been shown that there was no essential difference in the assay result whether isolated cells or nuclei were used (8).
OECD (2002).
Also different methods to isolate cells/nuclei (e.g. homogenizing, mincing, enzymic digestion and mesh filtration) gave comparable results (55).
Guidance Document on the Recognition, Assessment and Use of Clinical Signs as Humane Endpoints for Experimental Animals Used in Safety Evaluation, OECD Environment, Health and Safety Publications (EHS), Series on Testing and Assessment, št. 19, OECD Publishing, Pariz.
Consequently, either isolated cells or isolated nuclei can be used.
Gelska elektroforeza posamezne celice v alkalnih pogojih
A laboratory should thoroughly evaluate and validate tissue-specific methods of single cell/nuclei isolation.
občutljiva tehnika za zaznavanje poškodb primarne DNK na ravni posamezne celice/jedra.
As discussed in paragraph 40, the persistence of some of the lesions that lead to the DNA strand breaks detected by the comet assay may be very short (52) (53).
Komet
Therefore, whatever method is used to prepare the single cell/nuclei suspensions, it is important that tissues are processed as soon as possible after the animals have been euthanised and placed in conditions that reduce the removal of lesions (e.g. by maintaining the tissue at low temperature).
oblika, ki jo zavzamejo nukleoidi, ko so izpostavljeni enemu elektroforeznemu polju, poimenovana zaradi svoje podobnosti kometu: glava je jedro, v repu pa je DNK, ki je v električnem polju migrirala iz jedra.
The cell suspensions should be kept ice-cold until ready for use, so that minimal inter-sample variation and appropriate positive and negative control responses can be demonstrated.
Ključna spremenljivka/parameter
PREPARATION OF SLIDES
spremenljivka protokola, ki lahko zaradi majhne spremembe močno vpliva na sklepno ugotovitev preskusa.
Slide preparation should be done as soon as possible (ideally within one hour) after single cell/nuclei preparation, but the temperature and time between animal death and slide preparation should be tightly controlled and validated under the laboratory's conditions.
Ključne spremenljivke so lahko specifične za tkivo.
The volume of the cell suspension added to low melting point agarose (usually 0,5-1,0 %) to make the slides should not reduce the percentage of low melting point agarose to less than 0,45 %.
Ključne spremenljivke se ne smejo spreminjati, zlasti v okviru preskusa, ne da bi se pretehtal vpliv takih sprememb na odziv v preskusu, na primer kot to določajo stopnja in variabilnost pozitivnih in negativnih kontrol.
The optimum cell density will be determined by the image analysis system used for scoring comets.
V poročilu o preskusu morajo biti navedene spremembe ključnih spremenljivk, izvedene med preskusom ali v primerjavi s standardnim protokolom za laboratorij, in za vsako spremembo je treba podati utemeljitev.
It is therefore recommended that the lysis conditions be kept as constant as possible for all slides within an experiment.
Iz te vrednosti je razvidna količina prelomov DNK, izražena v odstotkih.
Once prepared, the slides should be immersed in chilled lysing solution for at least one hour (or overnight) at around 2-8 °C under subdued lighting conditions e.g. yellow light (or light proof) that avoid exposure to white light that may contain UV components.
TRENUTNE OMEJITVE PRESKUSA
After this incubation period, the slides should be rinsed to remove residual detergent and salts prior to the alkali unwinding step.
V okviru trenutnega znanja je s kometnim preskusom in vivo povezanih več omejitev.
This can be done using purified water, neutralization buffer or phosphate buffer.
Te omejitve naj bi se zmanjšale ali ožje opredelile na podlagi vedno več izkušenj z uporabo preskusa za reševanje varnostnih vprašanj v regulativnem okviru.