Time–concentration–effect models in predicting chronic toxicity from acute toxicity data

2001 ◽  
Author(s):  
Foster Mayer ◽  
Mark Ellersieck ◽  
Gary Krause ◽  
Kai Sun ◽  
Gunhee Lee ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Chronic Toxicity ◽  
Toxicity Data

scholarly journals Toxic Effects of Cannabis and Cannabinoids: Animal Data

2005 ◽  
Vol 10 (suppl a) ◽  
pp. 23A-26A ◽  
Author(s):  
Pierre Beaulieu
Keyword(s):  
Acute Toxicity ◽  
Present Article ◽  
Chronic Toxicity ◽  
Toxic Effects ◽  
Acute Administration ◽  
Toxicity Data ◽  
Toxicity Studies ◽  
Animal Data ◽  
Animal Toxicity

The present article reviews the main toxic effects of cannabis and cannabinoids in animals. Toxic effects can be separated into acute and chronic classifications. Acute toxicity studies show that it is virtually impossible to die from acute administration of marijuana or tetrahydrocannabinol, the main psychoactive component of cannabis. Chronic toxicity involves lesions of airway and lung tissues, as well as problems of neurotoxicity, tolerance and dependence, and dysregulations in the immune and hormonal systems. Animal toxicity data, however, are difficult to extrapolate to humans.

Development of an Acceptable Factor To Estimate Chronic End Points From Acute Toxicity Data

1985 ◽  
Vol 1 (4) ◽  
pp. 261-269 ◽  
Author(s):  
Bradly C. Venman ◽  
Christine Flaga
Keyword(s):  
Acute Toxicity ◽  
Chronic Toxicity ◽  
Daily Intake ◽  
Toxicity Data ◽  
Acceptable Daily Intake ◽  
End Points ◽  
Uncertainty Factors ◽  
Daily Exposure

Acceptable daily intake (ADI) values are routinely developed for threshold toxicants from NOAELs determined from human or animal chronic or subchronic data. These NOAELs are then divided by appropriate uncertainty factors ranging from 10 to 1000 depending on the quality of the data. However, for the vast majority of chemicals used industrially, adequate toxicity data needed to use this process are not available. Thus, a procedure to estimate a chronic toxicity endpoint from acute toxicity data, such as an oral rat LD50, becomes necessary. An acute-to-chronic application factor of 0.0001 was developed, which when multiplied by an oral LD50 for an individual chemical, yields a surrogate chronic NOAEL. This figure can then be used to estimate an acceptable daily exposure for humans. The process used to estimate this application factor is detailed.

Survey for Tributyltin in Water and Sediment in Canada in 1999

2005 ◽  
Vol 40 (4) ◽  
pp. 431-447 ◽  
Author(s):  
R. James Maguire ◽  
Suzanne P. Batchelor
Keyword(s):  
Acute Toxicity ◽  
Pest Control ◽  
Marine Sediments ◽  
Chronic Toxicity ◽  
Aquatic Organisms ◽  
Benthic Organisms ◽  
Freshwater Sediments ◽  
Antifouling Paints ◽  
Water And Sediment ◽  
Small Craft

Abstract A survey of water and sediment from 152 harbours, marinas and shipping channels across Canada was conducted in 1999 to determine the extent of contamination by tributyltin (TBT) prior to the total ban on its antifouling uses being phased in over the period 2003 to 2008, and to assess the effectiveness of the 1989 regulation of antifouling uses of TBT under the Canadian Pest Control Products Act. TBT was found in sediments in this survey much more frequently than in water. The main conclusion was that by 1999 the regulation had been generally effective in reducing TBT contamination in water, but not sediment, in small-craft marinas and harbours. TBT continued to be found in some freshwater and seawater locations frequented by larger vessels, that could have been legally painted at the time with TBT antifouling paints, at concentrations that could cause chronic toxicity to aquatic organisms. TBT was also found in many marine sediments, and some freshwater sediments, at concentrations that could cause chronic toxicity to sensitive benthic organisms. In addition, TBT concentrations in many marine sediments could cause acute toxicity to sensitive benthic organisms. Because of the long persistence of TBT in sediments, it may pose a hazard to benthic organisms in some locations in Canada for many years after the total ban on antifouling uses of TBT.

Effects of atrazine and alachlor on self-purification processes in receiving streams

1996 ◽  
Vol 33 (6) ◽  
pp. 181-187 ◽  
Author(s):  
Jana Zagorc-Koncan
Keyword(s):  
Adverse Effect ◽  
Acute Toxicity ◽  
Toxicity Test ◽  
Chronic Toxicity ◽  
Acute Toxicity Test ◽  
Organic Substances ◽  
Inhibiting Effect ◽  
Scenedesmus Subspicatus ◽  
Net Assimilation ◽  
Chlorophyll A Content

In recent years many waterways in Slovenia have been subjected to an increased loading with pesticides due to intensification of agriculture. The most widely used herbicides are atrazine and alachlor and they were detected in some rivers and even in ground water. Therefore the effects of atrazine and alachlor on selfpurification processes were investigated. The basic selfpurification processes studied were biodegradation of organic substances and photosynthesis and growth of algae. The inhibiting effect of pesticides on the process of biodegradation of organic pollutants was evaluated by the use of laboratory river model and mathematical modelling. The harmful impacts of pesticides on aquatic autotrophic organisms were assessed by measurement of net assimilation inhibition (24-h acute toxicity test) as well as growth inhibition - chlorophyll- a content (72-h chronic toxicity test) of algae Scenedesmus subspicatus. The results obtained demonstrate that atrazine and alachlor in concentrations found in our rivers have practically no effect on biodegrading heterotrophic organisms, while their adverse effect on algae is quite considerable.

scholarly journals Histopathological Assessment of the Effect of Pregabalin Toxicity on Cerebrum and Cerebellum of Adult Albino Rats

2021 ◽  
Author(s):  
Wael Abdou Hassan ◽  
Shaimaa Shehata ◽  
Ahmad ElBana
Keyword(s):  
Cerebral Cortex ◽  
Acute Toxicity ◽  
Chronic Toxicity ◽  
Control Group ◽  
Albino Rats ◽  
Histopathological Study ◽  
Addictive Behaviors ◽  
Group 3 ◽  
Group 2 ◽  
Cerebral Cortex Tissue

Abstract Background: Pregabalin (PGB) used as analgesic in treatment of neurogenic pains of chronic diseases, is considered as one of the most abused anti-epileptic drugs worldwide and it has been proved that it induces addictive behaviors. The present histopathological study aimed to identify the effect of PGB administration on cerebral cortex and cerebellar cortex, in both acute and chronic toxicity. Seventy-two male and non-pregnant female adult albino rats’ 6- to 8-week-old divided into 3 main groups of 24 rats each were studied. Group 1 represented the control group and group 2 represented the acute toxicity group, in which rats were given a single dose of PGB (5000 mg/kg) orally by gavage and after 24 hours, rats were sacrificed and examined. Group 3 represented the chronic toxicity group; were given PGB 500 mg/kg orally by gavage for 12 weeks, after which rats were sacrificed and examined. Result: Cerebral cortex tissue of acute toxicity group displayed astrocytosis and dystrophic changes, while in chronic group showed degeneration, necrosis and cellular infiltrates. The cerebellum of chronic groups showed degeneration and shrunken of Purkinje cells. Conclusion: Acute and chronic intoxication with pregabalin adversely altered the structure of cerebral cortex and cerebellum.

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