natgillin/translations-raw huggingface dataset:
It is a precursor of egg yolk proteins and, once produced in the liver, travels in the bloodstream to the ovary, where it is taken up and modified by developing eggs.
Cu toate acestea, interpretarea efectelor poate fi consolidată prin alte niveluri de tratament care nu sunt afectate de toxicitatea sistemică.
Vitellogenin is almost undetectable in the plasma of immature female and male fish because they lack sufficient circulating oestrogen; however, the liver is capable of synthesising and secreting vitellogenin in response to exogenous oestrogen stimulation.
Există unele aspecte care trebuie luate în considerare pentru acceptarea rezultatelor testului.
Vitellogenin induction has also been demonstrated following exposure to aromatisable androgens (8, 9).
Valori mari ale VTG la masculii din grupele de control ar putea compromite performanța testului și capacitatea acestuia de a detecta agoniștii estrogenici slabi.
A reduction in the circulating level of oestrogen in females, for instance through the inhibition of the aromatase converting the endogenous androgen to the natural oestrogen 17β-estradiol, causes a decrease in the VTG level which is used to detect chemicals having aromatase inhibiting properties (10, 11).
Valori mici ale VTG la femelele din grupele de control ar putea compromite performanța testului și capacitatea acestuia de a detecta inhibitorii aromatazei și antagoniștii estrogenici.
The biological relevance of the vitellogenin response following oestrogenic/aromatase inhibition is established and has been broadly documented.
Studiile de validare au fost utilizate pentru a elabora orientarea respectivă.
However, it is possible that production of VTG in females can also be affected by general toxicity and non-endocrine toxic modes of action, e.g. hepatotoxicity.
În ceea ce privește cuantificarea producției de ouă, aceasta este supusă unor variații importante [coeficientul de variație (CV) poate varia de la 20 la 60 %] care afectează capacitatea testului de a detecta o scădere semnificativă a producției de ouă mai mică decât 70 % pe măsură ce valoarea CV se apropie de 50 % sau mai mult.
Several measurement methods have been successfully developed and standardised for routine use.
Atunci când CV este limitat la valori mai scăzute (în jur de 20-30 %), testul va avea o putere acceptabilă (80 %) pentru a detecta o scădere cu 40-50 % a producției de ouă.
This is the case of species-specific Enzyme-Linked Immunosorbent Assay (ELISA) methods using immunochemistry for the quantification of VTG produced in small blood or liver samples collected from individual fish (12, 13, 14, 15, 16, 17, 18).
Conceperea testului utilizat pentru Pimephales promelas, care include patru duplicate pentru fiecare nivel de tratament, ar trebui să acorde mai multă putere parametrului de fecunditate, în comparație cu un test cu doar două duplicate.
Fathead minnow blood, zebrafish blood or head/tail homogenate, and medaka liver are sampled for VTG measurement.
În cazul în care un laborator nu a mai realizat testul anterior sau au fost efectuate modificări substanțiale (de exemplu, schimbarea subspeciei sau a furnizorului de pești), se recomandă efectuarea unui studiu de competență tehnică.
In medaka, there is a good correlation between VTG measured from blood and from liver (19).
Se recomandă utilizarea unor substanțe chimice care prezintă o gamă de moduri de acțiune sau de impacturi asupra unor parametri studiați.
Appendix 6 provides the recommended procedures for sample collection for VTG analysis.
Practic, fiecare laborator este încurajat să își elaboreze propriile date istorice de control pentru masculi și femele și să efectueze teste cu o substanță chimică de control pozitivă pentru activitatea estrogenică (de exemplu, 17β-estradiol la 100 ng/l sau un agonist slab cunoscut) având ca rezultat creșterea VTG la masculi, cu o substanță de control pozitiv în vederea inhibării aromatazei (de exemplu, fadrozol sau procloraz la 300 μg/l) având ca rezultat scăderea VTG la femele și cu o substanță chimică de control pozitiv pentru activitatea androgenică (de exemplu 17β-trenbolonul la 5 μg/l) având ca rezultat inducerea caracteristicilor sexuale secundare la femelele de Pimephales promelas și de Oryzias latipes.
Kits for the measurement of VTG are widely available; such kits should be based on a validated species-specific ELISA method.
Toate aceste date pot fi comparate cu datele disponibile din studiile de validare (1, 2, 3) pentru a garanta competența laboratorului.
Secondary sex characteristics in male fish of certain species are externally visible, quantifiable and responsive to circulating levels of endogenous androgens; this is the case for the fathead minnow and the medaka — but not for zebrafish which does not possess quantifiable secondary sex characteristics.
În general, măsurătorile vitelogeninei trebuie considerate pozitive în cazul unei creșteri semnificative statistic a VTG la masculi (p < 0.05) sau în cazul unei scădere semnificative statistic la femele (P < 0.05) cel puțin la doza maximă testată în comparație cu grupul de control și în absența semnelor de toxicitate generală.
Females maintain the capacity to develop male secondary sex characteristics, when they are exposed to androgenic chemicals in water.
Un rezultat pozitiv este confirmat suplimentar prin demonstrarea unei relații plauzibile din punct de vedere biologic între doză și curba răspunsurilor.
Several studies are available in the scientific literature to document this type of response in fathead minnow (20) and medaka (21).
Astfel cum s-a menționat anterior, scăderea vitelogeninei poate să nu fie în totalitate de origine endocrină; cu toate acestea, un rezultat pozitiv trebuie să fie interpretat, în general, ca o dovadă a activității endocrine in vivo și trebuie să genereze în mod normal acțiuni pentru clarificări suplimentare.
A decrease in secondary sex characteristics in males should be interpreted with caution because of low statistical power, and should be based on expert judgement and weight of evidence.
Evaluarea histopatologică a gonadelor poate fi solicitată de autoritățile de reglementare pentru a determina capacitatea de reproducere a animalelor testate și pentru a permite realizarea unei evaluări probatorii a rezultatelor testului.
There are limitations to the use of zebrafish in this assay, due to the absence of quantifiable secondary sex characteristics responsive to androgenic acting chemicals.
Efectuarea examinării histopatologice a gonadelor se poate dovedi de prisos în cazul unor valori pozitive ale VTG sau ale caracteristicilor sexuale secundare (și anume, creșterea sau scăderea VTG sau inducerea caracteristicilor sexuale secundare).
In the fathead minnow, the main indicator of exogenous androgenic exposure is the number of nuptial tubercles located on the snout of the female fish.
OCDE (2006b).
In the medaka, the number of papillary processes constitutes the main marker of exogenous exposure to androgenic chemicals in female fish.
Vitellogenin induction by 17b-estradiol and 17a-ethinylestradiol in male zebrafish (Danio rerio).
Appendix 5A and Appendix 5B indicate the recommended procedures to follow for the evaluation of sex characteristics in fathead minnow and in medaka, respectively.
C. 131: 531-539.
The 21-day fish assay includes the evaluation of quantitative egg production and preservation of gonads for optional histopathology examination.
Development of an ELISA for determination of the hepatic vitellogenin in Oryzias latipes (Oryzias latipes).
Some regulatory authorities may require this additional endpoint for a more complete evaluation of the reproductive fitness of the test animals, or in cases where vitellogenin and secondary sex characteristics did not respond to the chemical exposure.
OCDE (2010).
Although some endpoints may be highly diagnostic (e.g. VTG induction in males and tubercle formation in females), not all endpoints (e.g. fecundity and gonad histopathology) in the assay are intended to unequivocally identify specific cellular mechanisms of action.
ABREVIERI ȘI DEFINIȚII
Rather, the suite of endpoints, collectively, allows inferences to be made with regard to possible endocrine disturbances and thus provide guidance for further testing.
o substanță sau un amestec
Although not endocrine specific, fecundity, due to its demonstrated sensitivity across known endocrine active chemicals (5), is an important endpoint to include because when it and other endpoints are unaffected one is more confident that a compound is not likely endocrine active.
coeficient de variație
However, when fecundity is affected it will contribute heavily in weight of evidence inferences.
test de imunoadsorbție cu anticorpi marcați enzimatic
Guidance on data interpretation and acceptance of test results is provided further in this test method.
Axul HPG
Definitions used in this test method are given in Appendix 1.
axul hipotalamo-hipofizo-gonadal
In the assay, male and female fish in a reproductive status are exposed together in test vessels.
Rata de încărcare
Their adult and reproductive status enables a clear differentiation of each sex, and thus a sex-related analysis of each endpoint, and ensures their sensitivity towards exogenous chemicals.
greutatea umedă a peștelui per volum de apă.
At test termination, sex is confirmed by macroscopic examination of the gonads following ventral opening of the abdomen with scissors.
CMT
An overview of the relevant bioassay conditions are provided in Appendix 2.
concentrația maximă tolerată, reprezentând aproximativ 10 % din CL50 (concentrația letală)
The assay is normally initiated with fish sampled from a population that is in spawning condition; senescent animals should not be used.
Densitatea populației
Guidance on the age of fish and on the reproductive status is provided in the section on Selection of fish.
numărul de pești pe unitatea de volum de apă.
The assay is conducted using three chemical exposure concentrations as well as a water control, and a solvent control if necessary.
vitelogenina este o fosfolipoglicoproteină precursoare a proteinelor din vitellus care în mod normal apare la femelele active din punct de vedere sexual din toate speciile ovipare.
Two vessels or replicates per treatment are used for zebrafish (each vessel containing 5 males and 5 females).
CONDIȚII EXPERIMENTALE PENTRU TESTUL DE SCREENING ENDOCRIN LA PEȘTI
Four vessels or replicates per treatment are used for fathead minnow (each vessel containing 2 males and 4 females).
Tipul testului
This is to accommodate the territorial behaviour of male fathead minnow while maintaining sufficient power of the assay.
În regim dinamic
Four vessels or replicates per treatment are used for medaka (each vessel containing 3 males and 3 females).
Temperatura apei
The exposure is conducted for 21-days and sampling of fish is performed at day 21 of exposure.
Calitatea iluminatului
Quantitative fecundity is monitored daily.
Becuri fluorescente (spectru larg)
On sampling at day 21, all animals are killed humanely.
Intensitatea luminii
Secondary sex characteristics are measured in fathead minnow and medaka (see Appendix 5A and Appendix 5B); blood samples are collected for determination of VTG in zebrafish and fathead minnow, alternatively head/tail can be collected for the determination of VTG in zebrafish (Appendix 6); liver is collected for VTG analysis in medaka (Appendix 6); gonads are fixed either in whole or dissected for potential histopathological evaluation (22).
10-20 μE/ m2/s, 540-1000 lux, sau50-100 ft-c (niveluri ambientale de laborator)
TEST ACCEPTANCE CRITERIA
12-16 h de lumină, 12-8 h de întuneric
For the test results to be acceptable the following conditions apply:
< 5 g/l
the mortality in the water (or solvent) controls should not exceed 10 per cent at the end of the exposure period;
Dimensiunea camerelor de testare
the dissolved oxygen concentration should be at least 60 per cent of the air saturation value (ASV) throughout the exposure period;
10 (minimum)
the water temperature should not differ by more than ± 1,5 °C between test vessels at any one time during the exposure period and be maintained within a range of 2 °C within the temperature ranges specified for the test species (Appendix 2);
2 (minimum)
evidence should be available to demonstrate that the concentrations of the test chemical in solution have been satisfactorily maintained within ±20 % of the mean measured values;
5 (minimum)
evidence that fish are actively spawning in all replicates prior to initiating chemical exposure and in control replicates during the test.
Volumul soluției de testare
oxygen and pH meters;
(minimum)
equipment for determination of water hardness and alkalinity;
4 (minimum)
adequate apparatus for temperature control and preferably continuous monitoring;
Volumele soluțiilor de testare schimbate
tanks made of chemically inert material and of a suitable capacity in relation to the recommended loading and stocking density (see Appendix 2);
Minimum 6/zi
spawning substrate for fathead minnow and zebrafish, Appendix 4 gives the necessary details.
Minimum 5/zi
suitably accurate balance (i.e. accurate to ± 0,5 mg).
Vârsta organismelor testate
Any water in which the test species shows suitable long-term survival and growth may be used as test water.
A se vedea punctul 21.
The pH of the water should be within the range 6,5 to 8,5, but during a given test it should be within a range of ± 0,5 pH units.
Greutatea umedă aproximativă a peștilor adulți (g)
In order to ensure that the dilution water will not unduly influence the test result (for example by complexion of test chemical); samples should be taken at intervals for analysis.
Femele: 1,5 ± 20 %
Measurements of heavy metals (e.g. Cu, Pb, Zn, Hg, Cd, and Ni), major anions and cations (e.g. Ca2+, Mg2+, Na+, K+, Cl–, and SO42–), pesticides (e.g. total organophosphorus and total organochlorine pesticides), total organic carbon and suspended solids should be made, for example, every three months where dilution water is known to be relatively constant in quality.
masculi: 2,5 ± 20 %
If water quality has been demonstrated to be constant over at least one year, determinations can be less frequent and intervals extended (e.g. every six months).
Femele: 0,35 ± 20 %
Some chemical characteristics of acceptable dilution water are listed in Appendix 3.
masculi: 0,35 ± 20 %
The stock solution should preferably be prepared by simply mixing or agitating the test chemical in dilution water by using mechanical means (e.g. stirring or ultrasonication).
Femele: 0,65 ± 20 %
Saturation columns (solubility columns) can be used for achieving a suitable concentrated stock solution.
masculi: 0,4 ± 20 %
However, in case a solvent is necessary, a solvent control should be run in parallel, at the same solvent concentration as the chemical treatments.
Nr. de pești per vas de testare
For difficult to test chemicals, a solvent may be technically the best solution; the OECD guidance document on aquatic toxicity testing of difficult substances and mixtures should be consulted (23).
6 (2 masculi și 4 femele)
The choice of solvent will be determined by the chemical properties of the substance or mixture.
6 (3 masculi și 3 femele)
The OECD guidance document recommends a maximum of 100 μl/l, which should be observed.
10 (5 masculi și 5 femele)
However a recent review (24) highlighted additional concerns when using solvents for endocrine activity testing.
Nr. de tratamente
Therefore it is recommended that the solvent concentration, if necessary, is minimised wherever technically feasible (dependent on the physical-chemical properties of the test chemical).
= 3 (plus controalele corespunzătoare)
A flow-through test system will be used.
Nr. de vase per tratament
Such a system continually dispenses and dilutes a stock solution of the test chemical (e.g. metering pump, proportional diluter, saturator system) in order to deliver a series of concentrations to the test chambers.
Nr. de pești pentru fiecare concentrație testată
The flow rates of stock solutions and dilution water should be checked at intervals, preferably daily, during the test and should not vary by more than 10 % throughout the test.
16 femele adulte și 8 masculi adulți (4 femele și 2 masculi în fiecare vas duplicat)
Care should be taken to avoid the use of low-grade plastic tubing or other materials that may contain biologically active chemicals.
12 femele adulte și 12 masculi adulți (3 femele și 3 masculi în fiecare vas duplicat)
When selecting the material for the flow-through system, possible adsorption of the test chemical to this material should be considered.
10 femele adulte și 10 masculi adulți (5 femele și 5 masculi în fiecare vas duplicat)
Test fish should be selected from a laboratory population, preferably from a single stock, which has been acclimated for at least two weeks prior to the test under conditions of water quality and illumination similar to those used in the test.
Regimul de hrănire
It is important that the loading rate and stocking density (for definitions, see Appendix 1) be appropriate for the test species used (see Appendix 2).
Adulți sau nauplius de Artemia de două sau de trei ori pe zi (ad libitum), hrană disponibilă în comerț sau o combinație a celor menționate
mortalities of greater than 10 % of population in seven days: reject the entire batch;
Nauplius de Artemia de două sau trei ori pe zi (ad libitum), hrană disponibilă în comerț sau o combinație a celor menționate
mortalities of between 5 % and 10 % of population: acclimation for seven additional days; if more than 5 % mortality during second seven days, reject the entire batch;
Nauplius de Artemia de două sau trei ori pe zi (ad libitum), hrană disponibilă în comerț sau o combinație a celor menționate
mortalities of less than 5 % of population in seven days: accept the batch.
Fără aerare, cu excepția cazului în care concentrația de oxigen dizolvat este sub 60 % din valoarea de saturație din aer
Fish should not receive treatment for disease during the acclimation period, in the pre-exposure period, or during the exposure period.
Apa de diluție
Pre-exposure and selection of fish
Apă curată de suprafață, din puțuri sau reconstituită sau apă de la robinet declorizată
The one to two-week pre-exposure period is recommended with animals placed in vessels similar to the actual test.
Perioada de preexpunere
Fish should be fed ad libitum throughout the holding period and during the exposure phase.
Perioadă recomandată de 714 zile
The exposure phase is started with sexually dimorphic adult fish from a laboratory supply of reproductively mature animals (e.g. with clear secondary sexual characteristics visible as far as fathead minnow and medaka are concerned), and actively spawning.
Durata expunerii la substanța chimică
For general guidance only (and not to be considered in isolation from observing the actual reproductive status of a given batch of fish), fathead minnows should be approximately 20 (± 2) weeks of age, assuming they have been cultured at 25 ± 2 °C throughout their lifespan.
Parametri biologici studiați
Japanese medaka should be approximately 16 (± 2) weeks of age, assuming they have been cultured at 25 ± 2 °C throughout their lifespan.
supraviețuire
Zebrafish should be approximately 16 (± 2) weeks of age, assuming they have been cultured at 26 ± 2 °C throughout their lifespan.
comportament
Egg production should be assessed daily during the pre-exposure phase.
fecunditate
It is recommended that spawning be observed in all replicate tanks prior to inclusion in the exposure phase of the assay.
caracteristici sexuale secundare
Quantitative guidance on desirable daily egg production cannot be provided at this stage, but it is relatively common to observe average spawns of > 10 eggs/female/day for each species.
opțional examinare histopatologică a gonadelor
A randomised block design according to egg production output should be used to allocate replicates to the various experimental levels to ensure balanced distribution of replicates.
Criterii de acceptare a testului
TEST DESIGN
Oxigenul dizolvat ≥ 60 % din saturație; temperatura medie de 25 ± 2 °C; supraviețuire de 90 % la peștii de control; concentrații de testare măsurate în limita a 20 % din media valorilor măsurate pentru fiecare nivel de tratament
Three concentrations of the test chemical, one control (water) and, if needed, one solvent control are used.
Oxigenul dizolvat ≥ 60 % din saturație; temperatura medie de 26 ± 2 °C; supraviețuire de 90 % la peștii de control; concentrații de testare măsurate în limita a 20 % din media valorilor măsurate pentru fiecare nivel de tratament
The data may be analysed in order to determine statistically significant differences between treatment and control responses.
ANUMITE CARACTERISTICI ALE APEI DE DILUȚIE ACCEPTABILE
These analyses will inform whether further longer term testing for adverse effects (namely, survival, development, growth and reproduction) is required for the chemical, rather than for use in risk assessment (25).
COMPONENTĂ
For zebrafish, on day 21 of the experiment, males and females from each treatment level (5 males and 5 females in each of the two replicates) and from the control(s) are sampled for the measurement of vitellogenin.
CONCENTRAȚII
For medaka, on day 21 of the experiment, males and females from each treatment level (3 males and 3 females in each of the four replicates) and from the control(s) are sampled for the measurement of vitellogenin and secondary sex characteristics.
< 20mg/l
For fathead minnow, on day 21 of exposure, males and females (2 males and 4 females in each of the four replicates) and from the control(s) are sampled for the measurement of vitellogenin and secondary sex characteristics.
< 2mg/l
Quantitative assessment of fecundity is required, and gonadal tissues should be fixed in whole or dissected for potential histopathological evaluation, if required.
Amoniac neionizat
Selection of test concentrations
< 1μg/l
For the purposes of this test, the highest test concentration should be set by the maximum tolerated concentration (MTC) determined from a range finder or from other toxicity data, or 10 mg/l, or the maximum solubility in water, whichever is lowest.
< 10μg/l
The MTC is defined as the highest test concentration of the chemical which results in less than 10 % mortality.
Total pesticide organofosforice
Using this approach assumes that there are existing empirical acute toxicity data or other toxicity data from which the MTC can be estimated.
< 50ng/l
Estimating the MTC can be inexact and typically requires some professional judgment.
Apendicele 4A
Three test concentrations, spaced by a constant factor not exceeding 10, and a dilution-water control (and solvent control if necessary) are required.
SUBSTRATUL DE REPRODUCERE PENTRU PEȘTELE-ZEBRĂ
A range of spacing factors between 3,2 and 10 is recommended.
Tavă de reproducere
Selection and weighing of test fish
tavă instrumentară în întregime din sticlă, cu dimensiuni de exemplu de 22 × 15 × 5,5 cm (L × l × î), acoperită cu o sită mobilă din oțel inoxidabil (orificii de 2 mm).
It is important to minimise variation in weight of the fish at the beginning of the assay.
Sita trebuie să acopere deschiderea tăvii instrumentare la un nivel situat mai jos decât marginea acesteia.
Suitable size ranges for the different species recommended for use in this test are given in Appendix 2.
Substratul de reproducere se fixează pe sită.
For the whole batch of fish used in the test, the range in individual weights for male and female fish at the start of the test should be kept, if possible, within ± 20 % of the arithmetic mean weight of the same sex.
Se formează o structură în care pot pătrunde peștii.
It is recommended to weigh a subsample of the fish stock before the test in order to estimate the mean weight.
De exemplu, sunt adecvate plante de acvariu artificiale realizate din plastic de culoare verde (NB: trebuie luată în considerare posibila absorbție a substanței chimice de testare în materialul din plastic).
The test duration is 21 days, following a pre-exposure period.
Plasticul trebuie să fie curățat cu o cantitate suficientă de apă caldă pentru o perioadă suficientă de timp pentru a se asigura că nicio substanță chimică nu poate pătrunde în apa de testare.