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At least 19 recordsLinked to original sources
PubMed2004

Effects of bifenthrin on Daphnia magna during chronic toxicity test and the recovery test.

The acute and chronic toxic effects of bifenthrin on Daphnia magna were studied. The results showed that 24 h-EC50, 48 h-LC50 and 96 h-LC50 of bifenthrin on D. magna were 3.24, 12.40 and 1.40 microg/L respectively. And the LOEC and NOEC of bifenthrin were 0.02 and 0.004 microg/L respectively. The recovery test of bifenthrin on Daphnia magna was presented. Daphnia magna (F0 generation) were exposed during 21 d to different bifenthrin concentrations. Offspring (animals from the first and third brood: F1 (1st) and F1 (3rd), respectively) were transferred to a free pesticide medium during a 21 d recovery period. In this recovery study, survival, growth, reproduction (mean total young per female, onset of reproduction and number broods per female) and the intrinsic rate of natural increase (r) were assessed as parameters. Reproduction such as number of young per female as well as length was still reduced in F1 (1st) generation daphnids from parentals (F0) exposed to the bifenthrin. However F, (3rd) individuals from parentals exposed to pesticide concentrations were able to restore reproduction when a recovery period of 21 d was allowed, but the length of F, (3rd) from parentals exposed to the 0.5 and 0.75 microg/L bifenthrin concentration was still significantly effected (P < 0.05).

Animals↗
PubMed2006

Ecotoxicological assessment of effluents in the Basque country (Northern Spain) by acute and chronic toxicity tests using Daphnia magna straus.

Acute pass/fail, multi-concentration tests, and 3-brood chronic toxicity tests with Daphnia magna Straus (Cladocera, Crustacea) were used to characterise industrial and municipal effluents from various sources. The effluents that "passed" the pass/fail tests had 48-h EC50 values >100% and reproduction No Observed Effect Concentration (NOECs) > or =100%, except for one effluent that had a reproduction NOEC of 31.6%. The acute multi-concentration toxicity tests allowed a rapid classification of effluents from Very Toxic (48-h EC50 < 25%), to Non-Toxic (48-h EC50 >100%). The acute-to-chronic ratio (ACR: 48-h EC50 divided by the NOEC for reproduction) in the studied effluents ranged from 5 to about 100. From these results, we propose a step-wise protocol for assessing effluent toxicity. First, effluent is evaluated by means of simple and rapid pass/fail acute toxicity tests, to discriminate Non-Toxic from potentially Toxic effluents, thus facilitating the establishment of priority actions. Second, 48-h ECx is estimated to classify effluents on a toxicity scale from Non-Toxic to Very Toxic. Third, chronic multi-concentration tests are used to calculate reproduction NOECs. These parameters combined with data on effluent chemical composition, chemical and hydrological characteristics of receiving waters, and biological quality criteria can be jointly used for more rational regulatory practices and risk assessment of effluents.

Animals↗
PubMed2002

Silver speciation during chronic toxicity tests with the mysid, Americamysis bahia.

A 28-day chronic toxicity test and two 7-day chronic estimation toxicity tests were conducted with silver nitrate (AgNO(3)) and the marine invertebrate, Americamysis bahia, in 20 per thousand (parts-per thousand) salinity seawater. One 7-day test was initiated with 7-day-old mysids and the second was initiated with <24-h-old mysids. There was very good agreement between the three toxicity tests. The no-observed-effect concentration (NOEC) values from the 28-day test, the 7-day test initiated with 7-day-old mysids, and the 7-day test initiated with <24-h-old mysids were 34, 65 and 38 microg/l silver, respectively. The 96-h LC50 values from the 28-day toxicity test and the 7-day toxicity test initiated with 7-day old mysids were 260 microg/l, and the 96-h LC50 value from the 7-day toxicity test initiated with <24-h-old mysids was 280 microg/l. Free ionic silver, Ag(+), concentrations measured with a silver electrode were in good agreement with concentrations calculated using total dissolved silver and chloride concentrations. Mean measured concentrations of Ag(+) in the test solutions ranged from 0.99 to 25 ng/l for the dissolved silver concentrations that ranged from 34 to 410 microg/l silver, indicating that free ionic silver varied from 0.003 to 0.006% of the silver dissolved in the 20 per thousand salinity seawater. Understanding the relationship of salinity and silver speciation, and the effect of this relationship on chronic invertebrate toxicity, will be useful for development of a marine biotic ligand model (BLM) and a water quality criterion for silver. This model could provide an important tool for improving the relationship of laboratory toxicity test results and predicted effects in natural environments, where variations in salinity may act to modify the toxicity of silver and other metals.

Animals↗
PubMed2000

Comparison of four chronic toxicity tests using algae, bacteria, and invertebrates assessed with sixteen chemicals.

The performances of four chronic toxicity tests, comprising the Daphnia magna 21-day (d) (crustacean), Brachionus calyciflorus 2-d (rotifer), Pseudokirchneriella subcapitata 72-h (green algae), and the Microtox chronic 22-h (bacteria) tests, were compared. Sixteen chemicals with toxicity covering 6 orders of magnitude were studied. Very high correlations were found between the NOEC/EC(10) Pseudokirchneriella 72-h, NOEC/EC(10) Brachionus 2-d, and the NOEC Daphnia 21-d tests. The toxicological response of rotifers and microalgae were within the same order of magnitude as the response of Daphnia in 80% of cases (13/16 chemicals). The Microtox chronic test also anticipated the overall results of the Daphnia 21-d test, but the prediction was rather imprecise, compared with microalgae and rotifers. The test measuring the algal growth inhibition of P. subcapitata after 72h was the most sensitive bioassay. Toxicity on microalgae after 72h could be estimated after 5h by measuring either the direct fluorescence of either photosynthetic pigments or fluorescein diacetate in 56 and 43% of cases, respectively. The median value of the ratio between EC(10) and EC(50) was 3.75, 2, and 1.5 with the algae, the rotifers, and the bacteria, respectively.

Algorithms↗
PubMed2003

Identification of phototransformation products of prednisone by sunlight: toxicity of the drug and its derivatives on aquatic organisms.

Solar simulator irradiation of an aqueous suspension of prednisone, a widely prescribed drug, produces seven photochemical derivatives. The compounds have been identified on the basis of their physical features. All the chemicals have been tested to evaluate their toxic effects on freshwater organisms from different trophic levels. The rotifer Brachionus calyciflorus and two crustaceans, the cladoceran Daphnia magna and the anostracan Thamnocephalus platyurus, were used to perform acute toxicity tests. Chronic toxicity tests have been performed on the alga Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum) and the crustacean Ceriodaphnia dubia. The results showed low acute and chronic toxicity of prednisone. Some of the photoproducts had high toxic effects on C. dubia.

Animals↗
PubMed1999

International Conference on Harmonisation; guidance on the duration of chronic toxicity testing in animals (rodent and nonrodent toxicity testing); availability. Notice. Food and Drug Administration, HHS.

The Food and Drug Administration (FDA) is publishing a guidance entitled "S4A Duration of Chronic Toxicity Testing in Animals (Rodent and Nonrodent Toxicity Testing)." The guidance was prepared under the auspices of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) and is intended to provide guidance on the duration of chronic toxicity testing in rodents and nonrodents as part of the safety evaluation of a drug product. FDA is also noting circumstances in which it may accept durations of chronic toxicity testing in nonrodents that differ from the duration generally recommended by ICH.

Animals↗
PubMed2004

Assessment of a new cell culture perfusion apparatus for in vitro chronic toxicity testing. Part 1: technical description.

In vitro models for chronic toxicity, defined as a recurring exposure to compounds over a prolonged period of time, are still underrepresented in drug evaluation processes. The classical approach to cell culture is not readily suitable to long term repetitive applications. Therefore, we assessed the use of a commercially available perfusion cell culture apparatus in its applicability to chronic renal toxicity testing and describe the technical aspects of adopting the perfusion cell culture system to our purposes. It was apparent that there is a subtle dynamic difference between human renal proximal tubular cells cultured under perfusion and static conditions as illustrated by the accumulation of lactate dehydrogenase (LDH) and the secondary metabolism of resazurin to hydroresorufin, which occurred only under static conditions. The major achievement was the standardisation of the handling of this system with regard to cell cultivation, pH regulation, temperature regulation, and reproducibility of common toxicity endpoints.

Animal Testing Alternatives↗
PubMed2001

Chronic toxicity tests with Daphnia magna for examination of river water quality.

Chronic toxicity tests with Daphnia magna were applied for examination of river water quality. Water was sampled from the Maioka River in Yokohama City on May 14, 20, and 27, 1999, and used for the test after solid-phase extraction. The chronic test was carried out according to the OECD method. The duration was 21 days and the total number of live offspring produced per parent animal was counted. The results of the tests showed, survival rates of 100% using river water sampled on May 14 and 20 and the total numbers of live offspring produced per parent animal did not differ from the control. However, the survival rate of the sample collected on May 27 was 0% and the pesticides, fenitrothion, and thiobencarb were detected in the water. In addition to the river water samples, reconstituted water (Elendt M7) with additions of fenitrothion and thiobencarb was prepared to investigate mortality. When the reconstituted water with thiobencarb was applied to the test, the total number of live offspring produced per parent animal did not differ from the control. In contrast, when reconstituted water with fenitrothion was applied to the test, most parents were alive, but the total number of live offspring produced per parent animal was apparently different. The results of the above tests indicate that D. magna was affected not only by fenitrothion in the river water collected on May 27, but also by other factors that were not clarified in this study.

Animals↗
PubMed2004

Assessment of a new cell culture perfusion apparatus for in vitro chronic toxicity testing. Part 2: toxicological evaluation.

The goal of replacement, refinement and reduction of animal testing is critically dependent on the development and assessment of novel in vitro methodologies and the further development of existing methodologies. Here, we evaluated the use of a modified perfusion cell culture apparatus for application to chronic in vitro nephrotoxicity testing using DMSO, SDS, paracetamol and cyclosporine A as test compounds. Renal epithelial monolayers were cultured on microporous growth supports and exposed to test compounds under static or perfusion conditions. Alamar Blue reduction, gamma-glutamyl transpeptidase activity (GGT), lactate dehydrogenase activity (LDH) and remnant protein were used to assay cell toxicity. There was no significant difference in IC(50) values between static and perfusion cultures up to 72 hours exposure. However, the perfusion system allowed continuous real-time monitoring of plasma membrane damage, which gives important information of time, duration and scale of toxicity. The complexity of the system restrains its use to low-throughput analysis. However, the real and theoretical advantages of this and similar systems merit further investigations.

Acetaminophen↗
PubMed1984

[Chronic toxicity test of garlic extract in rats].

The influence of garlic extract on the chronic toxicity test were examined orally in Wistar rats for 6 months. There were no toxic symptoms due to garlic extract even at dose level of 2000 mg/kg for 5 times a week during 6 months. High dose of garlic extract did not inhibit the body weight gain, while the food consumption decreased slightly for the nutritional effects of it in both male and female rats. There were no significant differences in urinary, hematological and serological examinations compared each groups. In the histopathological findings, no toxic signs were observed on any of the tissues and organs examined.

Animals↗
PubMed1983

Toxicological studies on bestatin. III. Chronic toxicity test and recovery study in beagle dogs.

Chronic toxicity and its recovery of bestatin (NK421) was studied in both sexes of 28 Beagle dogs. At dose levels of 96, 38.4 and 15.4 mg/kg, NK421 was administered orally to dogs for 540 successive days. Control dogs were treated orally with 2 g/dog of corn starch. Each group consisted of 3 males and 3 females, and 2 males and 2 females were added to the 38.4 mg/kg group for a recovery test of 35 days. As general signs, anorexia, abnormal feces (loose stool, diarrhea, mucous stool), loss of activity, loss of lustre in fur, decoloration of the visible mucosa and emaciation were transiently observed in a early stage in 1 male and 1 female of the 96 mg/kg group. In correlation with these signs, slight anemia appeared hematologically, and the increased alkaline phosphatase activity and the decreased albumin ratio in serum protein fractions were observed biochemically. Except for the slight abnormal findings observed in the liver of the above 2 dogs, no significant changes were histopathologically noticed in any organ of all the dogs examined. The maximum non-toxic dose of NK421 in this study is estimated to be 38.4 mg/kg in dogs.

Animals↗
PubMed2004

Toxicity of the 13 priority pollutant metals to Vibrio fisheri in the Microtox chronic toxicity test.

The Microtox Acute Toxicity Test has been successfully used to measure the toxicity of metals and other pollutants at high concentrations (ppm) in selected environmental samples. However, metals and other toxicants are often found in much lower concentrations (ppb) in many municipal wastewaters and receiving waters. In order to assess the toxicity of these pollutants in these samples, a more sensitive toxicity assay is needed. The Microtox chronic toxicity test has been developed to measure the sublethal effect of toxicants over multiple generations of the test species, Vibrio fisheri. In this study, the toxicity of the 13 priority pollutant metals [i.e. As, Se, Cd, Cr (III and VI), Cu, Pb, Sb, Ag, Tl, Zn, Be, Hg and Ni] to V. fisheri was evaluated using the Microtox chronic toxicity test. In this test, the inhibitory concentration (IC), lowest observable effect concentration (LOEC), and no observable effect concentration (NOEC) were obtained after 22-h of incubation at 27+/-1 degrees C, by comparing the light output of the control to that of the test sample. Among the 13 priority pollutant metals, beryllium (Be) was found to be the most toxic in the test (LOEC=0.742-1.49 microg/l) while thallium (Tl) was the least toxic (LOEC=3840-15300 microg/l). The LOECs for copper (as Cu) and lead (Pb) in reagent (ASTM Type I) water were 6.78-13.6 microg/l and 626-1251 microg/l, respectively. The toxicity of copper sulfate (as Cu) in reagent water was shown and significantly reduced with the addition of natural organic matter (fulvic acid) or EDTA to the sample. The LOEC values for the 13 priority pollutant metals in this test were comparable to or lower than those reported for commonly used aquatic toxicity tests, such as the Ceriodaphnia dubia assay.

Benzopyrans↗
PubMed2006

A comparison of acute and chronic toxicity tests used to examine the temporal stability of a gradient in copper tolerance of Hediste diversicolor from the Fal estuary, Cornwall, UK.

The aim of this study was to use two different toxicity tests to verify the existence of a gradient in tolerance along Rostronguet Creek. Hediste diversicolor was collected from five populations in the Fal estuary previously shown to vary in copper tolerance. Exposure to 4 mgL(-1) of copper in an acute assay demonstrated that Mylor Creek worms were sensitive (LT(50) 86 h) and the tolerance of Rostronguet Creek worms increased moving upstream from the mouth of the creek (LT(50)s 100-258 h). There was no significant difference in tolerance between Mylor worms and worms from the mouth of Rostronguet Creek. This is in agreement with a previous study [Grant, A., Hateley, J.G., Jones, N.V., 1989. Mapping the ecological impact of heavy metals on the estuarine polychaete Nereis diversicolor using inherited metal tolerance. Marine Pollution Bulletin 20, 235-238] and demonstrates temporal stability of the gradient. Copper tolerance was also measured using a chronic toxicity test run for 90 d using step-wise increases in challenge concentration. A significant difference in tolerance was shown between populations from Mylor Creek and those at the mouth of Rostronguet Creek, which has not been reported previously. Experimental protocol was therefore an important factor in detecting population variation in tolerance.

Animals↗
PubMed2000

Sensitivity and significance of luminescent bacteria in chronic toxicity testing based on growth and bioluminescence.

This study explored the use of luminescent bacteria (Vibrio fischeri) for chronic aquatic toxicity tests. The evaluated inhibition of growth to Cu2+, Cr6+, Zn2+, Hg2+, Cd2+, Pb2+, cetyl-trimethylammonium bromide, 3,4-dichloroaniline, acetone, dimethylsulfoxide, ethanol, nitrobenzene, methanol, and 3,5-dichlorophenol was compared with results from another investigation, where the inhibition was determined by bioluminescence. Growth inhibition was found to indicate more reliably the presence of substances with chronic toxic properties than the loss of bioluminescence. But growth responded weaker to the majority of the analyzed toxicants than bioluminescence. This must be connected with the test parameters and the experimental conditions. But among growth experiments with freshwater bacteria species the sensitivity of the growth inhibition assay with V. fischeri is competitive when a poor medium is employed.

Luminescent Measurements↗