PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Toxicological evaluation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Toxicological evaluation of the staircase test for assessing fine motor movements.

A variety of tests have been developed to study neurotoxicant-related changes in motor function. However, despite recent advances, there remains a need for simple and specific tests of fine motor movements. Accordingly, we chose to evaluate whether a method developed for measuring changes in skilled movements following motor pathway lesions in rodents would provide a sensitive, specific, and economical approach to assessing fine motor control in the toxicology laboratory. We measured skilled paw reaching using the "staircase test" developed by Montoya et al. [Prog. Brain Res. 82 (1990) 459], in which a rat retrieves food pellets by reaching down from a central platform to a series of descending steps on either side, grasping the pellets in its forepaw, and lifting them to its mouth. Staircase boxes were scaled for the body weights of young adult male (350 g) and female (250 g) Long-Evans rats. Studies were conducted using harmaline, a tremorigen; scopolamine; methyl scopolamine; and 2,4-dithiobiuret (DTB), a compound that causes muscle weakness by interfering with cholinergic transmission at the neuromuscular junction. Harmaline (0, 1.0, 3.0, and 10.0 mg/kg) reduced pellet retrieval only at a dose that also caused visible tremor. Both scopolamine (0, 0.1, 0.3, and 1.0 mg/kg) and methyl scopolamine (0, 0.104, 0.312, and 1.04 mg/kg) impaired pellet retrieval; scopolamine was more effective than methyl scopolamine. DTB (5 daily doses of 0, 0.1, 0.2, and 0.5 mg/kg) had no effect on retrieval, even when causing visible signs of weakness. These data cast doubt on the utility of this method for detecting and quantifying subtle chemical-induced changes in motor function in rats.

Analysis of Variance↗
PubMed1990

[Organic-chemical air pollutants indoors--aspects of environmental toxicologic evaluation].

Indoor air pollution is characterized by a wide range of concentrations of many, mainly organic substances. To avoid adverse health effects it is necessary to develop indoor air quality standards. Standards should reflect the way and time of exposure and the fact that health risks might be possible especially to sensitive people. The toxicological basis for regulating indoor air quality is discussed. Special attention is given to organic substances with a cancerogenic and accumulating potential. An approach in setting standards of indoor air quality for frequent organic substances like toluene, xylene, styrene, dichloromethane, 1.1.1-trichloroethane, trichloroethene, tetrachloroethene, pentachlorophenol and PCB is presented, incorporating adequate protection margins. The results of this approach are compared with the WHO air quality guidelines and the German MIK values.

Air Pollutants↗
PubMed1985

[Toxicologic evaluation of nitrofuran derivatives].

The most important side effects of numerous nitrofuran derivatives are their mutagenicity and carcinogenicity. They are due to metabolites of this group of substances in the microbial and animal metabolism. The mutagenic or carcinogenic metabolites are either excreted or covalently bound in the animal organism and may then form persistent residues in the slaughtered animal. If active at all, such residues are toxicologically less active than free metabolites. To determine their bioavailability and to exclude any risk to the consumer, their relay-toxicity should be tested using suitable experimental animals.

Animals↗
PubMed2005

Toxicological evaluation of fucoidan extracted from Laminaria japonica in Wistar rats.

Fucoidans, the sulfated polysacchrides extracted from brown algae, have been extensively studied for their diverse biological activities. However, there is no detailed report investigating the toxicity of fucoidan. In this study, the acute and subchronic (6 months) toxicity of varying levels of fucoidan extracted from Laminaria japonica was investigated in Wistar rats after oral administration. The results showed that no significant toxicological changes were observed when 300 mg/kg body weight per day fucoidan was administered to rats. But when the dose was increased to 900 and 2500 mg/kg body weight per day, the clotting time was significantly prolonged. Besides this, no other signs of toxicity were observed. Based on these results, it can be concluded that the no adverse effect level of fucoidan from L. japonica is 300 mg/kg body weight per day.

Administration, Oral↗
PubMed2004

Toxicological evaluation of the ethanolic extract of Artemisia dracunculus L. for use as a dietary supplement and in functional foods.

TARRALIN is an ethanolic extract of Artemisia dracunculus (Russian tarragon), a common medicinal and culinary herb with centuries of use. Artemisia dracunculus is a close relative of the French or cooking tarragon and contains components common to many herbs that are routinely consumed without reported adverse effects. Since safety information of Artemisia dracunculus and its extract is limited to historical use, TARRALIN was examined in a series of toxicological studies. Complete Ames analysis did not reveal any mutagenic activity either with or without metabolic activation. TARRALIN was tested in an acute limit test at 5000 mg/kg with no signs of toxicity noted. In a 14 day repeated dose oral toxicity study, rats appeared to well tolerate 1000 mg/kg/day. Subsequently, TARRALIN was tested in an oral subchronic 90-day toxicity study (rat) at doses of 10, 100 and 1000 mg/kg/day. No noteworthy signs of toxicity were noted in feeding or body weight, functional observational battery or motor activity. Gross necropsy and clinical chemistry did not reveal any effects on organ mass or blood chemistry and microscopic examinations found no lesions associated with treatment. Therefore, TARRALIN appears to be safe and non-toxic in these studies and a no-observed adverse effect level in rats is established at 1000 mg/kg/day.

Animals↗
PubMed1996

[Toxicologic evaluation of pyrethroids in indoor air: demonstrated with the example of cyfluthrin and permethrin].

Pyrethroids have varying activities depending on vehicle or route of administration (oral, dermal, inhalational). Specific features like the sensory irritation potential of the alpha-cyano-pyrethroids on the respiratory tract can only be quantified adequately by inhalation testing. Thus equitoxic dosages can vary between inhalative and oral application, especially for alpha-cyano-pyrethrolds. The no-effect values for chronic exposures derived for permethrin (type I pyrethroid) and cyfluthrin (type II pyrethroid) show clearly, that each pyrethroid has to be considered as an individual substance toxicologically, and that any extrapolation from the oral to the inhalative route should only be done after a thorough assessment of the specific toxicological profile. The study of simulated pest control measures on carpets pretreated with permethrin showed, that no significant enrichment of permethrin in total dust could be seen from a carpet additionally treated with pyrethroids. The missing correlation between absolute (mg pyrethroid/m3 air) and relative (mg pyrethroid/kg dust) concentrations in air-borne dust as well as the low degree of translocation of pyrethroids from carpets (only about 0.044% x m(-2) x h(-1) of the cyfluthrin applied to the carpet can be regarded as possibly respirable) prove, that analyses of pyrethroids in household sedimented dust ("vacuum cleaner bag analyses") without knowing the absolute surface concentration and respective air concentrations are of little value for risk assessment. The data allow the conclusion, that a scientific assessment of health risks is only possible based on absolute concentrations of pyrethroids in indoor air.

Air Pollution, Indoor↗
PubMed1989

Toxicological evaluation of a poisoning attributed to ingestion of malathion insect spray and correlation with in vitro inhibition of cholinesterases.

A 24-year-old Caucasian male was found dead from unknown causes at his farm home. At the scene, partially filled bottles of ORTHO Malathion 50 Insect Spray and CLOROX bleach were found. At the time of autopsy, a strong odour of a petroleum based product was prominent in the small intestine and in the liquid stool. A similar odour was also present in the liquids of both bottles. Generalized visceral and vascular congestion with oedema in various tissues was markedly present. Toxicological analysis of the gastric contents, intestinal contents, bile and liquid samples from the malathion and bleach bottles revealed the presence of malathion in the concentrations of 2.1 g/kg, 98 g/kg, 570 mg/l, 54% and 11%, respectively. In the blood and urine, malathion was not detected. Xylenes and other common volatile components of the spray were detected in the liquids from the bottles and in the gastric and intestinal contents. The ability of the blood and bile samples to inhibit, in vitro, rat serum cholinesterase and electric eel acetylcholinesterase was consistent with their malathion concentrations as the bile inhibited both enzymes, while the blood did not. These findings conclude that the death was associated with the ingestion of a commercial malathion insect spray.

Acetylcholinesterase↗
PubMed1986

Toxicological evaluation of hydrochlorofluorocarbon 142b.

Groups of 110 rats of each sex were exposed by whole-body inhalation to 0, 1000, 10,000 or 20,000 ppm (v/v) of hydrochlorofluorocarbon 142b (CFC 142b or 1-chloro-1, 1-difluoroethane) for 6 hr/day, 5 days/wk for 104 wk (ten rats from each group were killed after 52 wk) in a combined chronic toxicity and oncogenicity study. Concurrently, ten male rats per group were exposed to the same concentrations for 13 wk in a bone-marrow cytogenicity study and another ten male rats per group were exposed for 15 wk in a dominant lethal study. No toxicologically significant compound-related effects were observed in behaviour, appearance, growth, clinical pathology, or gross and microscopic pathology. Respiratory infection and consequently higher than expected mortality during the first year did not compromise the studies or conclusions but may have contributed to the intergroup differences in the numbers of chromosome breaks and acentric fragments. No evidence for mutagenic potential was seen in either the dominant lethal or the cytogenetic assays. These data indicate the very low toxicity of CFC 142b with respect to chronic effects and genotoxic and oncogenic potential. The toxicological profile of CFC 142b is similar to that of other chlorofluorocarbons that have been assigned a threshold limit value (TLV) of 1000 ppm as a workplace 8-hr time-weighted average by the American Conference of Governmental Industrial Hygienists.

Animals↗
PubMed1988

[Toxicological evaluation of pesticide and chemical residues in control of biological processes in vegetables under glass and plastics].

The cultivation of vegetables under glass and plastics is one of the most intensive application fields of pesticides and chemicals for regulation of biological processes. Therefore it may potentially occur a relatively high residues contamination of the crops. The author reveals in a survey the residue situation of usual insecticides, acaricides, fungicides, and chemicals for regulation of biological processes on tomatoes, cucumbers, and lettuce in comparison with the maximum residue limit after cold fogging application. The residues of benomyl, carbendazim, and ethylen-bis-dithiocarbamate are detailed discussed in the light of the latest toxicological findings. The results the residues of 11 agents on the crops show that after the corresponding preharvest interval the residues constitute 1.7-78% of the maximum residue limit. The conclusion is drawn that the cold fogging application of the agents under glass and plastics does not result in food hygienic toxicological problems.

Drug Residues↗