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PubMed2004

Toxicological evaluation of expanded shredded tobacco stems.

A tiered testing strategy has been developed to evaluate the potential of tobacco processes, ingredients, or technological developments to change the biological activity resulting from burning tobacco. The strategy is based on comparative chemical and biological testing. Expanded shredded tobacco stems (ESS) constitute an example of a common tobacco components expansion process currently used in the manufacture of cigarettes to increase the tobacco blend filling capacity. As part of the toxicological evaluation of ESS, test cigarettes containing 9.5%, 18.5%, and 25% ESS were compared to control cigarettes containing 0% ESS. Testing included mainstream cigarette smoke chemistry studies, genotoxicity studies (Ames and sister chromatid exchange), a 13-week inhalation study in Sprague-Dawley rats, and a 30-week dermal tumor promotion study in SENCAR mice. Collectively, data indicated that cigarettes with and without ESS had a similar toxicological profile in this test battery.

Animals↗
PubMed2003

Toxicological evaluation of dry ice expanded tobacco.

A tiered testing strategy has been developed to evaluate the potential of tobacco processes, ingredients, or technological developments to change the biological activity resulting from burning tobacco. The strategy is based on comparative chemical and biological testing. Dry ice expanded tobacco (DIET) is an example of a common tobacco expansion process currently used in the manufacture of cigarettes to increase tobacco filling capacity. As part of the toxicological evaluation of DIET, test cigarettes containing DIET were compared with control cigarettes containing tobacco expanded with a traditional expansion agent (Freon-11, also known as trichlorofluoromethane). Testing included mainstream cigarette smoke chemistry studies, genotoxicity studies (Ames and sister chromatid exchange, SCE), a 13-week inhalation study in Sprague-Dawley rats, and a 30-week dermal tumor promotion study in SENCAR mice. Cigarettes containing DIET or Freon-11 expanded tobacco were similar in biological activity.

Administration, Inhalation↗
PubMed2003

Toxicological evaluation of propane expanded tobacco.

A tiered testing strategy has been developed to evaluate the potential for tobacco processes, ingredients, and other technological developments to increase or decrease the biological activity resulting from burning tobacco. The strategy is based on comparative chemical and biological testing. Propane expanded tobacco is an example of a processed tobacco used in the modern manufacture of cigarettes. Test cigarettes containing propane expanded tobacco were compared to control cigarettes containing tobacco expanded with a traditional expansion agent (Freon-11). The toxicological evaluation included chemistry studies using mainstream cigarette smoke (determination of selected constituent yields), in vitro studies using cigarette smoke condensate (Ames study in Salmonella typhimurium and sister chromatid exchange study in Chinese hamster ovary cells) and in vivo studies (13-week inhalation study of mainstream cigarette smoke in Sprague-Dawley rats and 30-week dermal tumor promotion study of cigarette smoke condensate in SENCAR mice). Although statistically significant differences in several smoke constituents were observed, most constituents from cigarettes containing 100% propane expanded tobacco were within market survey ranges. Furthermore, biological tests indicated that the cigarettes containing propane or Freon-11 expanded tobacco were not significantly different.

Administration, Inhalation↗
PubMed2006

Research strategies for safety evaluation of nanomaterials. Part VI. Characterization of nanoscale particles for toxicological evaluation.

To properly assign mechanisms or causes for toxic effects of nanoscale materials, their properties and characteristics both outside and within the biological environment must be well understood. Scientists have many tools for studying the size, shape, and surface properties of particulates outside of the physiological environment; however, it is difficult to measure many of these same properties in situ without perturbing the environment, leading to spurious findings. Characterizing nanoparticle systems in situ can be further complicated by an organism's active clearance, defense, and/or immune responses. As toxicologists begin to examine nanomaterials in a systematic fashion, there is consensus that a series of guidelines or recommended practices is necessary for basic characterization of nanomaterials. These recommended practices should be developed jointly by physical scientists skilled in nano characterization and biological scientists experienced in toxicology research. In this article, basic nanoparticle characterization techniques are discussed, along with the some of the issues and implications associated with measuring nanoparticle properties and their interactions with biological systems. Recommendations regarding how best to approach nanomaterial characterization include using proper sampling and measurement techniques, forming multidisciplinary teams, and making measurements as close to the biological action point as possible.

Drug Evaluation, Preclinical↗
PubMedDate not supplied

Toxicological evaluation of an electrically heated cigarette. Part 4: Subchronic inhalation toxicology.

The biological activity of mainstream smoke from an electrically heated cigarette (EHC) with controlled combustion and from the University of Kentucky Reference Cigarette 1R4F was determined in Sprague Dawley rats exposed nose-only for 90 days, 6 h a day, 7 days per week. For an equivalent response comparison between the two cigarette types, two doses were chosen for the EHC where the anticipated results were in the dynamic range of the 1R4F dose-response curve (four concentrations) for most end points. The number of cigarettes smoked per m(3) of diluted smoke resulted in total particulate matter concentrations of 40 and 90 microg l (-1) for the EHC and 40-170 microg l (-1) for the 1R4F. Biomonitoring indicated achievement of target doses. Mainstream smoke yields were lower for the EHC, with the exception of formaldehyde. No smoke-related mortality, remarkable in-life observations or abnormal gross pathological findings were observed. Smoke- and dose-related clinical pathology and organ weight changes included: increases in segmented neutrophils, some liver parameters and lung and adrenal weight relative to body weight; and decreases in lymphocytes, glucose concentration and spleen weight. Smoke-related histopathological findings in the respiratory tract included epithelial cell hyperplasia, squamous metaplasia, atrophy and accumulation of pigmented alveolar macrophages; they were mostly dose-dependent, more pronounced in the upper than lower respiratory tract and completely or partially reversed by 6 weeks post-inhalation. Qualitatively, the biological effects seen for the EHC and the 1R4F were comparable and similar to those observed in other mainstream smoke inhalation studies. Quantitatively, the biological activity of the EHC mainstream smoke was, on average, 65% lower than that of the 1R4F mainstream smoke on an equal cigarette basis and equivalent activity on an equal TPM basis.

Administration, Inhalation↗
PubMed2005

Developmental toxicology evaluations--issues with including neurotoxicology and immunotoxicology assessments in reproductive toxicology studies.

Developmental and reproductive toxicology (DART) has routinely been a part of safety assessment. Attention is now focused on the effects of chemicals on the developing nervous and immune systems. This focus on developmental neurotoxicology (DNT) and developmental immunotoxicology (DIT) is based on the premise that children differ from adults in some aspects of their biology and, thus, may also differ in their responses to chemicals. This session's objective was to discuss issues common to DNT and DIT as they relate to DART protocols, including high dose selection and maternal toxicity, adequacy of pup exposure during lactation, use of a different dosing paradigm for DART versus DNT or DIT studies, and whether DIT and DNT endpoints can be incorporated into a single DART study for hazard identification purposes. Consensus was achieved on all topics except the adequacy for risk assessment purposes of the use of a limited number of endpoints for DIT and DNT, with the DNT endpoints being the primary focus of disagreement. Panelists indicated that a combination study design for hazard identification was feasible, though flexibility to meet the scientific needs of the project was emphasized. The adequacy of existing triggers for additional developmental studies was also questioned. Panelists iterated the importance of understanding pup exposure during the various life stages and the use of toxicokinetic data in designing these studies. The group agreed to consider the HESI ACSA Life Stages Task Force recommendations as a next step to address some of the issues and challenges raised during this session.

Abnormalities, Drug-Induced↗
PubMed1994

[Extension of toxicologic evaluation standards in environmental medicine exemplified by use of bovine somatotropin (BST) in food production--an interdisciplinary study].

In food hygiene, the substances used are evaluated exclusively according to toxicological criteria. As a result of the increasing possibilities of intervention, e.g., by means of hormonal control of life processes, the question is raised as to whether the relationship in health--that of the human being to his environment--may also be affected by the use of substances in a manner other than toxicological. In the case of bovine somatotropin (BST) it is shown that external hormonal control intervenes in the organism's own regulation and correspondingly limits the capability of experiencing nonhuman subjectivity. The resulting health consequences are discussed on the basis of a semiotics of the environment which allocates a sign background to the toxicological process.

Animal Husbandry↗
PubMed1977

Toxicological evaluations of some brominated biphenyls.

Extensive toxicological studies were carried out to define the probable hazard of octabromobiphenyl (OBB) to workers, users, and the environment. OBB had low acute toxicity in mammals and birds by various routes of administration. It was essentially non-irritating to rabbit eyes, non-irritating to human skin and caused only mild skin irritation and no sensitization in the guinea pig. OBB caused equivocal effects in the rat fetus. OBB was stored in the body fat of rats and caused liver enlargement at high single doses or low repeated doses. The studies indicate probable low safety factors in application and use and probable bioaccumulation. Hexabromobiphenyl (HBB) was more acutely toxic than OBB by skin absorption in the rabbit and caused liver enlargement at lower single doses.

Abnormalities, Drug-Induced↗
PubMed1998

[Analysis and toxicological evaluation of hazardous gases in sealed cabin].

82 volatile organic compounds (VOCs) of eight organic sorts and 3 target inorganic compounds in a sealed cabin that simulating the flying spaceship were identified and quantified for 5 d, the law of hazardous gas concentration variation was discussed, and the atmosphere toxicology was evaluated preliminarily. It provides a basis for detecting gas compounds and evaluating the atmosphere toxicology in the spaceship.

Air Pollutants↗
PubMed2001

[Toxicological evaluation of diagnostic methods used for poisoning with psychoactive substances].

Toxicological diagnosis in cases of intoxication with psychoactive substances known in clinical and forensic toxicology requires appropriate laboratory studies. The paper pertains evaluation of the currently employed techniques of quantitative and qualitative analysis of psychoactive substances in a biological material. Usefulness of the most frequently applied screening (immunochemical) approaches and the confirmation (physicochemical) techniques was evaluated against the validation criteria, relating to the specificity, detection limit and sensitivity of the discussed substances.

Humans↗
PubMed1991

Toxicological evaluation of agromet (Metalaxyl) preparation.

A complex toxicological study was carried out in relation to the hygienic standardization of the fungicide preparation Ridomil, whose forthcoming production in this country will be under the name Metalaxyl. The study was performed on sexually mature white rats of both sexes, at oral, dermal and inhalation exposure, acute, subacute and chronic experiments, according to the Bulgarian State Standard. Besides the routine toxicological studies were carried also studies for establishing the long-term effects of the preparation (gonadotropic, embryotoxic and teratogenic, cardiovascular). The results from the study permitted the Agromet preparation to be put in III class--moderately toxic according to limiting index LD50 oral. On the basis of data from the authors study on the general toxicity and long-term effects of Metalaxyl a temporary MAC 4 mg/m3 was proposed.

Alanine↗
PubMed1989

Reproductive and developmental toxicological evaluation of sanguinaria extract.

Reproductive and developmental toxicology studies were conducted with orally administered sanguinaria extract in rats and rabbits. Groups of animals which received no test article served as controls in all studies reported. No adverse effects on estrous cycling, male or female copulatory and fertility indices or gestation/lactation parameters were observed in rats given 10-100 mg/kg/day. Reduced body weights in the offspring during lactation were observed at the 100 mg/kg/day treatment level concomitant with maternal toxicity. No developmental toxicity, including teratogenicity, was observed on the fetuses of rats following maternal administration of 5-60 mg/kg/day. An increase in post-implantation loss was observed at maternally toxic dosage levels of 50 and 75 mg/kg/day in rabbits. Oral administration of sanguinaria extract in a perinatal and postnatal study in rats caused no adverse effects on litter size, parturition, or lactation of female rats nor on survival and growth of their offspring at dosage levels of 5-60 mg/kg/day. Maternal oral toxicity thresholds were 60 mg/kg/day in rats and 25 mg/kg/day in rabbits. It was concluded that the oral intake of sanguinaria extract has no selective effect on fertility, reproduction or fetal and neonatal development in rats or rabbits.

Alkaloids↗
PubMed1986

Genetic toxicology evaluation of the novel semi-synthetic antibiotic piperacillin.

Piperacillin (T-1220, Pipracil) a semi-synthetic antibiotic was evaluated in a battery of genetic toxicology assays. The assays employed were: the microbial assay, the host mediated assay, the microbial assay incorporating urine samples from mice dosed with piperacillin, the in vivo cytogenetic assay, and the dominant lethal assay. In all assays, piperacillin produced consistent negative results indicating that piperacillin does not have mutagenic potential.

Animals↗
PubMed1989

Ciprofloxacin: toxicologic evaluation of additional safety data.

Long-term ciprofloxacin toxicology studies, additional data on arthorpathogenic effects, embryotoxicity studies in monkeys, and further results on central nervous system/interaction toxicology are presented. In the long-term studies of rats and mice, ciprofloxacin was given as food admixture in concentrations up to 5,000 ppm for 24 and 21 months, respectively. This treatment regimen did not result in any systemic toxicity and also did not give any indication of a tumorigenic effect of ciprofloxacin. In a study of juvenile dogs to investigate development of arthropathogenic lesions using magnetic resonance imaging techniques, an increase in width of the recessus suprapatellaris occurred only in those dogs in which marginal effects developed. Thus, this technique may be a suitable method to monitor juvenile patients receiving ciprofloxacin. Ciprofloxacin was also studied for its potential to act as an abortifacient when given orally or parenterally to cynomolgus monkeys. The data obtained did not give any indication of teratogenicity or embryolethality, and mean patterns of progesterone were similar between routes of administration, dose groups, and controls. Finally, data are presented that demonstrate that central nervous system interaction toxicity between quinolones and nonsteroidal anti-inflammatory drugs can be observed in rats only at therapeutically irrelevant high dose levels.

Abortion, Spontaneous↗
PubMed1999

Toxicological evaluation of cyclosporine eyedrops.

PURPOSE: The short-term toxicological effects of two cyclosporine A eyedrop formulations are compared. METHODS: Formula A was based on Sandimmune (Novartis, Switzerland) infusion concentrate with a final ethanol concentration of 1% (w/w), and formula B on Sandimmune oral solution. Both formulations were diluted in sterile peanut oil (10 mg/ml). The left eyes of 12 rabbits were treated with the cyclosporine eyedrops over a two-week period. The right eyes served as controls. Slit-lamp and scanning electron microscopic examinations were performed, and the total protein concentration in aqueous humor was measured in treated and control eyes. RESULTS AND CONCLUSION: Both Sandimmune oral solution and infusion concentrate-derived eyedrops were found to be non-toxic to rabbit eyes and there were no significant differences between the two formulations. More definite conclusions as to the safety of these cyclosporine formulations cannot be made without long-term trials.

Animals↗