[Show abstract][Hide abstract] ABSTRACT: Effects of common anaesthetics such as ether, methoxyflurane, isoflurane, carbon dioxide (at 100%, 80% or 60% admixed with O(2)) on toxicity and clinical pathology parameters in rats were investigated. Ether, methoxyflurane and 100% CO(2) induced toxicity in some animals. Erythrocyte, haemoglobin and haematocrit were reduced in females by 100% CO(2), methoxyflurane and isoflurane. Glucose was increased by 60% CO(2), 80% CO(2), ether, isoflurane and methoxyflurane in males. Chloride was reduced by isoflurane and all CO(2) concentrations in females. Serum proteins were reduced by isoflurane and methoxyflurane. Sodium, inorganic phosphate, calcium and magnesium were reduced by methoxyflurane and isoflurane, but increased by all CO(2) concentrations. Potassium was reduced by ether, methoxyflurane or isoflurane. Triiodothyronine and thyroxine were reduced by all anaesthetics. Prolactin was reduced by methoxyflurane, but raised by ether and isoflurane. Erythrocyte cholinesterase (E-ChE) activity is markedly reduced (20-40%) after anaesthesia with all CO(2) concentrations in both sexes. E-ChE was unaffected by ether, methoxyflurane, or isoflurane. Serum and brain cholinesterase activities were not affected. E-ChE inhibition correlated with decreased blood pH, suggesting that this was caused by acidosis. This is of practical relevance in the risk assessment of cholinesterase inhibitors. Conclusions: Clinical pathology data were affected by all anaesthetics. CO(2)/O(2) (80%/20%) and isoflurane are the most suitable anaesthetics. If E-ChE activity is to be determined, isoflurane is the anaesthetic of choice.
Full-text · Article · Oct 2007 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: Ethylbenzene was administered to groups of male and female Wistar rats by gavage for 4 (n = 5/dose/sex) and 13 weeks (n = 10/dose/sex) (OECD 408) at doses of 0 (vehicle control), 75, 250, and 750 mg/kg bodyweight/day (mg/kg bw/day), administered am/pm as half doses. In the 4-week study, > or =250 mg/kg increased serum alanine aminotransferase, total bilirubin and cholesterol, liver weights and centrilobular hepatocyte hypertrophy, and kidney weights; males also had post-dose salivation, increased urinary epithelial cell casts and cells, and hyaline droplet nephropathy. In the 13-week study, > or =250 mg/kg increased water consumption and produced post-dose salivation. Liver-related effects: increased serum alanine aminotransferase, gamma-glutamyltransferase, bilirubin, total protein, albumin and globulins, cholesterol, liver weights and centrilobular hepatocyte hypertrophy, and reduced prothrombin times. Kidney-related effects: increased serum potassium, calcium, magnesium, kidney weights, and (males only) urea and hyaline droplets in renal tubular epithelium, and reduced sodium (females only); creatinine was reduced in 750 mg/kg males. The NOAEL of ethylbenzene in these studies, based on hepatocyte hypertrophy and liver- and kidney-related clinical chemistry changes, was 75 mg/kg bw/day.
Full-text · Article · May 2007 · Archive für Toxikologie
[Show abstract][Hide abstract] ABSTRACT: Pulmonary irritant threshold concentrations of two hexamethylene-1,6-diisocyanate (HDI)-based prepolymers (I: polymeric emulsfier modified and II: oligomeric allophanate modified) were determined in acute inhalation studies according to TRGS 430 (Dangerous Substances Technical Rule, isocyanates, Germany), based on benchmark extrapolation of bronchoalveolar lavage fluid (BALF) total protein. It was also investigated if the method is robust enough to be transferred to an independent laboratory. Five male Wistar rats per group were exposed nose-only to the test substances as liquid aerosols to concentrations of 0, 0.5, 3, 15 mg/m(3) for both test substances with an additional test group at 50 mg/m(3) for test substance I. The duration of the exposure was 6h, followed by serial sacrifices 1 day, 3 days and 7 days post exposure. BALF was analyzed for biochemical and cytological markers indicative for injury of the bronchoalveolar region. The exposure of rats to test substance I and II caused dose depended lung irritation with BALF total protein concentration being the most sensitive indicator of pulmonary effects. The extrapolated no observed adverse effect level of test substance I was 1.1 mg/m(3) and that of test substance II 2.3 mg/m(3). The acute pulmonary irritant threshold concentrations were found to be similar to those reported by [Pauluhn, J., 2004. Pulmonary irritant potency of polyisocyanate aerosols in rats: comparative assessment of irritant threshold concentrations by bronchoalveolar lavage. J. Appl. Toxicol. 24, 231-247] for HDI-homopolymers and other HDI-based polyisocyanates, and were at least 30 times higher than the MAK (occupational exposure limit) value for the HDI monomer (0.035 mg/m(3)). Thus the EBW (exposure assessment value) for these two HDI-based prepolymers can be established at 10x MAK, i.e. at 0.35 mg/m(3).
No preview · Article · Mar 2007 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: Wistar rats continuously received octyl methoxycinnamate (OMC) in the diet through two successive generations at nominal doses of 0, 150, 450 or 1000 mg/kg bw/day. OMC had no adverse effects on estrous cycles, mating behavior, conception, parturition, lactation and weaning, sperm and follicle parameters, macropathology and histopathology of the sexual organs. 1000 mg/kg bw/day reduced parental food consumption and body weight (-14% to -16% in males, -4% to -5% females), increased liver weight, produced hepatic cytoplasmic eosinophilia and erosion/ulceration of glandular stomach mucosa. and led to a slightly decreased implantation rate in the top dose F0 and F1 dams. The high dose F1 and F2 pups had reduced lactation weight gain and organ weights and delayed sexual maturation landmarks. There was no evidence of a selective influence of the test compound on pups' sexual landmarks. The NOAEL (no observed adverse effect level) is 450 mg/kg bw/day for fertility and reproductive performance, for systemic parental and developmental toxicity.
No preview · Article · Aug 2005 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: 4-Chloro-2-carboxyphenoxyacetic acid (CCPA) residues have occasionally been observed in crops treated with 4-chloro-2-methylphenoxyacetic acid (MCPA). The oral toxicity of MCPA and CCPA was compared in a 4-week rat study at a dietary concentration of 2000 ppm. CCPA was also given at 12,000 ppm (equivalent to 1g/kg bodyweight/day). MCPA at 2000 ppm caused reduced food consumption and body weight gain and increased water consumption in females only. Changes in clinical chemistry confirmed the liver as a target organ. Increased serum creatinine and urobilinogen, degenerated transitional epithelial cells in the urine showed that the kidney was also affected. Response to CCPA was confined to the 12,000 ppm dose. The target organs were liver and kidney as for MCPA. Microscopic examination revealed an increased severity of basophilic tubules and calcification at the outer/inner medulla transition in the kidneys. The results demonstrate that CCPA is less toxic than MCPA, that CCPA has no different toxicological end points when compared to MCPA, and that any risks associated with consumption of CCPA will not be underestimated if the CCPA residue is treated as if it were parent MCPA. Based on the MCPA-CCPA comparison, criteria for read across and minimal information requirements are proposed.
No preview · Article · Jul 2005 · Regulatory Toxicology and Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Wistar rats were exposed to 2-methoxypropylacetate-1 (2-MPAc-1) vapours in concentrations of 0, 110, 560 and 2800 ppm for (equiv. to 0; 0.6; 3.0 and 14.9 mg/L) for 4 weeks in chambers (6 hours/day; 5 days/week; five male and five female animals per group). The top concentration was equivalent to a 95% vapour saturation at 20 degrees C and the animals reacted to this with a moderate respiratory irritation during the 6 hours exposure times; at 560 ppm these effects were only slight. The top dose was also associated with a significantly reduced body weight development and some hematologic and biochemical alterations of little specificity. The most prominent effect was thymic atrophy. No effects were noted on the testes or on the cellularity in blood or bone marrow. 560 ppm were without systemic effects. Furthermore, 2-methoxypropanol-1 (2-MP-1), 2-MPAc-1 and 2-ethoxyethanol (EE) were administered in parallel by gavage to groups of five male Wistar rats daily for 10 days at near equimolar dose levels (1800, 2600 and 1800 mg/kg per day, respectively). At the end of the administration period the testes were investigated. There was a pronounced testicular atrophy in animals exposed to EE, whereas no adverse effects were observed with 2-MP-1 and 2-MPAc-1. The results of these studies indicate that 2-MP-1 and 2-MPAc-1 which previously had been shown to exert pronounced prenatal toxicity in rabbits and weak prenatal effects in rats are devoid of other forms of systemic toxicity in rats that are typically observed with ethoxyethanol and methoxyethanol.
No preview · Article · Mar 2005 · Human & Experimental Toxicology
[Show abstract][Hide abstract] ABSTRACT: Styrene has been shown to cause an increase in the incidence of lung tumors in CD-1 mice following chronic exposure at 40 and 160 ppm, whereas no treatment-related increase in tumors in any organ was seen in rats chronically exposed to up to 1000 ppm styrene. So far most of the mechanistic studies have been performed with male animals. The aim of the present study was to further elucidate the target cell population in mouse lungs exposed to styrene, and to investigate possible differential in vivo effects (e.g., glutathione depletion, increased lipid peroxidation, and oxidative DNA damage). Groups of female CD-1 mice were exposed to styrene at concentrations of 0, 172 or 688 mg/m3 (0, 40 or 160 ppm) for 6 h per day on 1 day, 5 consecutive days or for 20 days during a 4 week period. Groups of female Crl:CD rats were exposed to styrene at concentrations of 0, 688 or 2150 mg/m3 (0, 160 or 500 ppm) for a single 6 h period or for 6 h per day on 5 consecutive days. No signs of lung toxicity were observed in rats. The cytology of cells in lung lavage fluid provided no signs of an inflammatory response in either rats or mice. In mice, both exposure levels caused decreased CC16 protein concentrations in lung lavage fluid after 1 and 5 exposures and in mouse blood serum throughout the study, suggesting that styrene may cause destruction of Clara cells in mice. Degenerative lesions in mouse Clara cells (vacuolar cell degeneration, cell necrosis) were revealed by electronmicroscopy. After 5 and 20 exposures of mice at 160 ppm, cellular crowding, expressed as an irregular epithelial lining and indicative of a very early hyperplasia was noted. Although a depletion of glutathione was noted in mouse lung homogenates after 20 exposures, there was no evidence of oxidative stress as indicated by unchanged concentrations of 8-OH-deoxyguanosine. Malondialdehyde, an indicator of lipid peroxidation, was slightly increased in mice after 1 exposure at 160 ppm only.
Full-text · Article · Nov 2004 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: Kollidon VA 64 (copovidone, CAS-No. 25086-89-9) was administered in the diet to male and female Wistar rats (0, 700, 1400, and 2800 mg/kg body weight) for 24 months, and to male and female beagle dogs (0, 500, 1500, and 2500 mg/kg body weight/day) for 52 weeks. Clinical signs, body weight, food consumption, hematology, and gross and histopathological evaluations were conducted on both rats and dogs, and dogs also underwent hearing tests, ophthalmoscopic examinations, electrocardiograms, blood pressure measurement, and clinical chemistry and urinalysis evaluations. No adverse in-life observations related to treatment were observed in either species. The rats exhibited dark discoloration of the feces that was attributed to the intake and excretion of large amounts of test substance and was not considered to be an adverse effect. No treatment-related hematological changes, or gross or histopathological lesions were observed in either species that could be considered clinically relevant. Vacuolated histiocytosis in the mesenteric lymph nodes of four dogs that was not accompanied by inflammation or degenerative changes reflected histiocytic removal and degradation of the test article rather than a toxic effect. The results of these studies demonstrate the absence of any significant toxicological findings of high dietary levels copovidone in rats and dogs, resulting in no-observed-adverse-effect levels of 2800 mg/kg body weight/day in rats and 2500 mg/kg body weight/day in dogs, the highest doses tested.
Preview · Article · Nov 2004 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: Early indicators of aniline hydrochloride (AH) toxicity were investigated in male Fisher 344 rats for 1 or 4 weeks at dietary dose levels of 10, 30 or 100 mg/kg body weight (bw)/day (actual intake at least 6, 17 and 57 mg/kg). The doses were based on earlier studies that had shown spleen toxicity and carcinogenicity in male rats at 100 mg/kg/day but not at 10 mg/kg/day. In the present study a dose-related formation of haemoglobin adducts and Heinz bodies was found from 10 and 30 mg/kg bw/ day, respectively, onwards. Signs of anaemia (decreased red blood cell counts and increased reticulocytes) were recorded from 30 mg/kg onwards. At 100 mg/kg, an overt haemolytic anaemia was associated with increases in serum transferrin concentration and total iron binding capacity in the blood reflecting major perturbations in iron metabolism. At this dose there was an increase in peripheral neutrophil leucocytosis in the blood, indicating an inflammatory process in the spleen. Histopathologic evaluation showed a focal perisplenitis and haemosiderin deposition in sinusoidal Kupffer cells of the liver at 100 mg/kg. These results corroborate the contention that carcinogenic doses of aniline cause early effects on haematological parameters, inflammatory reaction in the spleen and perturbations in iron metabolism as a result of haemolytic anaemia. Accordingly, the carcinogenicity of aniline may be linked to definable threshold-related processes.
No preview · Article · Sep 2004 · Human & Experimental Toxicology
[Show abstract][Hide abstract] ABSTRACT: The antithyroid acting drug propylthiouracil (PTU) was administered to male and female Wistar rats at 0, 0.1, 1, or 10mg/kg body weight for 4 weeks according to the draft protocol of the "Enhanced OECD Test Guideline 407" (enhanced TG 407) in order to investigate its suitability to detect endocrine-mediated effects. The study was conducted with two identical subsets of five animals per sex and dose each to provide data on sensitivity. The modified protocol includes the investigation of additional organ weights, pathology, and histopathology, of thyroid hormones, of spermatozoa, and of estrus cycle. At time of sacrifice, all females were in the diestrus stage as prescribed. Adverse effects were observed in the thyroid gland (hypertrophy/ hyperplasia) and the pituitary gland (hyperplasia of basophilic cells, hypoplasia of acidophilic cells) together with dose-related decreased serum triiodothyronine (T3) and thyroxine (T4) levels and increased thyroid stimulating hormone (TSH) levels. Other effects of PTU included decrease of organ weights, anaemia, impaired blood coagulation, and reduced activity of enzymes. Hence, some of the additional examined endpoints of the enhanced TG 407, e.g., examination of pituitary gland and thyroid hormones, were suitable to detect endocrine-modulating effects of propylthiouracil. Treatment of five animals provides sufficient sensitivity to detect the described adverse effects of propylthiouracil. The enhanced TG is currently under investigation in several laboratories, evaluation of all the results will allow determining its practicability as well as the most suitable additional endpoints.
No preview · Article · Jan 2004 · Regulatory Toxicology and Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Synthetic crystalline lycopene provides an alternative to extracts of naturally occurring lycopene for use in dietary supplements and functional foods. BASF Lycopene 10 CWD and Lyco Vit 10% formulated products each contain approximately 10% synthetic lycopene. These products were evaluated for toxicological and behavioral effects during a 13-week oral dosing study with male and female Wistar rats. Doses of 0, 500, 1500 and 3000 mg/kg body weight/day Lycopene CWD and 3000 mg/kg body weight /day Lyco Vit, as well as 3000 mg/kg body weight /day of the matrices used to formulate and stabilize each product, were administered by gavage to 10 rats/sex/day. A satellite group of five rats/sex received 0 or 3000 mg/kg body weight /day of each formulated product for an interim evaluation at 4 weeks of feeding. No statistically significant, dose-related effects on body weight, body weight gain, food consumption, hematology, urinalysis, clinical chemistry or ophthalmoscopic parameters were seen in any of the lycopene product or lycopene formulation matrix groups in comparison to the vehicle control group after 4 or 13 weeks of dosing. No deaths attributed to the test articles occurred during the study and the only clinical finding and at necropsy was the presence of red pigment in the feces and gastrointestinal tract that was associated with the red-pigmented test materials. No significant or dose-related abnormalities were found at necropsy or in microscopic evaluations of tissues collected at termination. Rats evaluated in home cages or in open field tests for behavioral and sensorimotor effects during the final week of the study showed no signs of treatment-related effects. The no-observed-adverse-effect level (NOAEL) for this study was concluded to be 3000 mg/kg body weight/day for both Lycopene CWD and Lyco Vit. The results of this study thus demonstrate the absence of any significant toxicological findings with Lycopene CWD and Lyco Vit products even at very high dose levels.
No preview · Article · Dec 2002 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: Recently several chronic toxicity/carcinogenicity studies of di-isononyl phthalate (DINP) have been reported. These studies defined effect levels for liver tumors in male and female F344 rats at dietary levels exceeding 700 mg/kg/day; the no effect levels were 359 mg/kg/day in males and 442 mg/kg/day in females. Similar results were found in male B6C3F1 mice, but in female mice a significant increase in liver tumors was found at 336 mg/kg/day, making 112 mg/kg/day the NOAEL for liver tumors in that sex and species. DINP induces peroxisomal proliferation, and that, along with evidence that DINP is not mutagenic, is presumptive evidence for peroxisomal proliferation as the underlying mode of action for liver tumor development. To further explore the relationship between peroxisome proliferation and tumor induction in male and female mice, indicators of peroxisomal proliferation including liver weight, peroxisomal volume density, induction of peroxisomal enzyme activity, enhanced replicative DNA synthesis, and rates of apoptosis were measured at all of the dietary levels used in the chronic study in mice (500, 1500, 4000, and 8000 ppm, or approximately 100, 300, 800, and 1600 mg/kg/day). Liver weights, peroxisomal volume, and peroxisomal enzyme activity were significantly elevated in both male and female mice at the tumorigenic levels. Cell proliferation was also elevated in male and female mice, although the increases at levels below 4000 ppm in female mice were not significantly different from control values. Apoptosis was elevated at the 4000 and 8000 ppm levels, paralleling the increases in liver weight. These data along with previous results satisfy the criteria of the International Agency for Research on Cancer (IARC) and demonstrate that peroxisomal proliferation was indeed the mode of action for DINP-induced liver tumor induction in mice.
No preview · Article · Nov 2002 · Regulatory Toxicology and Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Differential patterns in terms of nephropathology and 8-hydroxyguanine formation in the course of oral 28-day studies were observed with nitrilotriacetic acid (NTA) and FeNTA. FeNTA, but not NTA, caused enhanced 8-hydroxyguanine formation in kidney DNA after oral and intraperitoneal administration. Enhanced lipid peroxidation in the kidney homogenate was observed with FeNTA as well as with NTA. For NTA, the low dose (9 mg/kg per day) was without adverse effect. The kidney toxicity of oral FeNTA (50, 200, and 1000 mg/kg per day) was only mild, 50 mg/kg per day; however, it still led to an increased 8-hydroxyguanine content. The relevance of Iron(III) (Fe(III)) or Fe(III)NTA formation as a relevant mediator of NTA-related toxicity was excluded on the basis of these data. Also, a thermodynamic consideration presented here, supports the view that zinc (Zn), and not Fe, is likely to mediate the tubular cell cytotoxicity of NTA.
No preview · Article · Sep 2002 · Human & Experimental Toxicology
[Show abstract][Hide abstract] ABSTRACT: A two-year feeding study in rats and an 18-month feeding study in mice were conducted to evaluate the potential chronic toxicity and oncogenicity of NMP in Crl:CD (SD)BR rats and B6C3F1/CrlBR mice. Groups of 62 male and female rats were administered diets containing 0, 1600, 5000, or 15,000 ppm of NMP for approximately 2 years. Groups of 50 male and female mice were administered diets containing 0, 600, 1200, or 7200 ppm NMP for approximately 18 months. In vivo parameters were evaluated weekly during the first 3 months of the study, and every other week or monthly during the remainder of the study. For rats, an ophthalmoscopic examination was conducted prior to study start and near the end of the study. Periodically, blood samples were collected from rats and mice for determination of leukocyte differential counts, and from mice for red blood cell morphology. After approximately 2 years of dietary administration in rats and 18 months in mice, all surviving animals were sacrificed. Selected tissues were processed for morphological evaluation. Over the course of the two-year study in rats, test substance-related decrements in body weight and weight gain occurred in 15,000 ppm males and females, which correlated with decreased food consumption and food efficiency. A toxicologically significant, test substance-related increase in the incidence of severe chronic progressive nephropathy occurred in 15,000 ppm males. Several morphological changes noted grossly and/or microscopically were secondary to the increased severity of chronic progressive nephropathy. NMP was not oncogenic in male or female rats at dietary concentrations of 15,000 ppm and below. A test substance-related decrease in the percentage of 15,000 ppm males surviving to the end of the two-year study compared to the control group resulted from the higher incidence of severe chronic progressive nephropathy. However, a sufficient population of 15,000 ppm rats were at risk for potential oncogenicity, so the lower survival did not impair the ability to detect an oncogenic response in this study. There were no adverse, test substance-related effects on the incidences of clinical observations, ophthalmic observations, or differential leukocyte counts in males or females, or on survival of females at any dietary concentration. Male and female mice administered dietary concentrations of 7200 ppm had significantly increased liver weight, significantly increased incidence of hepatocellular adenoma, and significantly increased foci of cellular alteration in the liver. At 7200 ppm, male mice also had an increased incidence of hepatocellular carcinoma while the increased incidence of hepatocellular carcinoma in female mice fell within the historical control range. In addition, the incidence of hepatocellular hypertrophy was increased in 7200 ppm males. Liver weight and hepatocellular hypertrophy were also increased in 1200 ppm males. There were no adverse, test substance-related effects on the incidences of clinical observations, food consumption, body weight, differential leukocyte counts, red blood cell morphology, or survival in either males or females at any dietary concentration. Under the conditions of the study, the no-observed-effect level for NMP was 5000 ppm for male and female rats, 600 ppm for male mice, and 1200 ppm for female mice.
No preview · Article · Dec 2001 · Drug and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: In mice, there were no effects on body weight or food consumption. As observed in rats, mice fed 2,500 or 7,500 ppm exhibited a change in urine coloration which was not associated with morphological changes in cholesterol, triglycerides, calcium, and alkaline phosphatase occurred at 28 days but not 90 days. These changes are thus assessed as being of minor toxicological relevance. Liver weights were elevated in males fed 2,500 or 7,500 ppm and centrilobular hypertrophy was seen in both sexes fed 7,500 ppm. These changes may be regarded as an adaptation process but are clearly related to NMP exposure. Other toxicological endpoints examined were unaffected by NMP. The NOAEL was 3,000 ppm for both sexes of rats based on body weight effects and changes in 3 neurobehavioral parameters (males only) at higher feeding levels. In mice, the NOAEL was 1,000 ppm based on liver responses to higher concentrations.
No preview · Article · Sep 1999 · Drug and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: A 90-day subchronic inhalation toxicity study was performed on Wistar rats in accordance to OECD testing guidelines to evaluate the toxicological profile of 2-ethylhexanol, potential target organs, and a no-observable-adverse-effect-level (NOAEL). 10 males and 10 females per group were exposed to 2-ethylhexanol vapours at concentrations of 15, 40 and 120 ppm (the latter corresponding to the vapour saturation at 20 degrees C) 6 hours/day for 90 days. The respective controls inhaled clean air under the same conditions. No substance-related adverse effects were observed for body weight, body weight gain, mortality, organ weights, clinical biochemistry and haematological parameters including clotting time. Cyanide-insensitive palmitoyl-CoA oxidation, a marker for peroxisome proliferation, was found elevated in a subchronic study in Fischer 344 rats after gavage application of 500 mg/kg but not under the conditions of this 90-day subchronic inhalation study. There were no findings related to the treatment with 2-ethylhexanol either at necropsy or at histological examination. The highest concentration tested under these conditions (120 ppm) was found to be the NOAEL for male and female rats.
No preview · Article · Apr 1998 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: 1. 90-day subchronic toxicity studies with 3-methyl-1-butanol (MEB) and 2-methyl-1-propanol (MEP) were performed on rats to evaluate the toxicological profile of the compounds under conditions of drinking water studies, to identify the potential target organs, and to determine no-observable-adverse-effect-levels (NOAELs) respective of the substances. The test substances were administered to groups of 10 male and 10 female Wistar rats in drinking water at concentrations of 0, 1000 p.p.m. (about 80 mg/kg/d), 4000 p.p.m. (about 340 mg/kg/d) and 16,000 p.p.m. (about 1250 and 1450 mg/kg/d of MEB and MEP respectively). 2. 16,000 p.p.m. was found to be the maximal concentration for both alcohols applicable to rats in drinking water. Higher concentrations had an influence on palatability and could thus not be tested in drinking water studies. 3. At 16,000 p.p.m. MEB a marginal increase in the red blood cell count as well as a slight decrease in the mean corpuscular volume and the mean corpuscular hemoglobin content was observed in males only. These changes are considered to be treatment-related, although the toxicological significance of these findings is unclear. No other substance-related effects were found on body weight (b.w.), mortality, various parameters of clinical chemistry, organ weights, gross pathology and histopathology. 4000 p.p.m. MEB did not cause any substance-induced changes. Therefore, the NOAEL of MEB was defined as 4000 p.p.m. for male and 16,000 p.p.m. for female rats under conditions of oral application via drinking water. 4. MEP concentrations up to and including 16,000 p.p.m. did not induce any signs of toxicity and were therefore defined as the NOAEL respective of this substance for rats under conditions of drinking water application.
No preview · Article · Jan 1998 · Human & Experimental Toxicology
[Show abstract][Hide abstract] ABSTRACT: 1 90-day subchronic toxicity studies with 3-methyl-1- butanol (MEB) and 2-methyl-1-propanol (MEP) were performed on rats to evaluate the toxicological profile of the compounds under conditions of drinking water studies, to identify the potential target organs, and to determine no-observable-adverse-effect-levels (NOAELs) respective of the substances. The test substances were administered to groups of 10 male and 10 female Wistar rats in drinking water at concentrations of 0, 1000 p.p.m. (about 80 mg/kg/d), 4000 p.p.m. (about 340 mg/kg/d) and 16 000 p.p.m. (about 1250 and 1450 mg/kg/d of MEB and MEP respectively).2 16 000 p.p.m. was found to be the maximal concentra tion for both alcohols applicable to rats in drinking water. Higher concentrations had an influence on palatability and could thus not be tested in drinking water studies.3 At 16 000 p.p.m. MEB a marginal increase in the red blood cell count as well as a slight decrease in the mean corpuscular volume and the mean corpuscular hemo globin content was observed in males only. These changes are considered to be treatment-related, although the toxicological significance of these find ings is unclear. No other substance-related effects were found on body weight (b.w.), mortality, various parameters of clinical chemistry, organ weights, gross pathology and histopathology. 4000 p.p.m. MEB did not cause any substance-induced changes. Therefore, the NOAEL of MEB was defined as 4000 p.p.m. for male and 16 000 p.p.m. for female rats under condi tions of oral application via drinking water.4 MEP concentrations up to and including 16 000 p.p.m. did not induce any signs of toxicity and were therefore defined as the NOAEL respective of this substance for rats under conditions of drinking water application.
No preview · Article · Dec 1997 · Human & Experimental Toxicology
[Show abstract][Hide abstract] ABSTRACT: In previous subchronic studies inhaled N-vinylpyrrolidone-2 (NVP) was haemotoxic, hepatotoxic and irritant to the nose. In the first of two long-term studies, study A, Sprague-Dawley rats were exposed by inhalation to 0, 5, 10 or 20 ppm NVP (6 hr/day, 5 days/wk) for 24 months. Satellite groups were killed after 3, 12 or 24 months. In study B, female Sprague-Dawley rats were exposed to 0 or 45 ppm NVP for 3 months and killed at 3 or 12 and 24 months post-exposure. In study A, survival was unaffected, but reduced body weight gain, haemotoxicity, effects on clinical chemistry parameters indicative of hepatotoxicity, increased liver weight, hepatocellular carcinomas, necrosis, reparative hyperplasia, adenomas and adenocarcinomas of the nasal cavity, and squamous cell carcinomas of the larynx were seen. Increased tumour incidence was seen only in the liver and upper respiratory tract. In study B, the effect of NVP on body weight evident at 3 months disappeared before 1 yr, but effects on liver pathology persisted throughout the subsequent 21-month exposure-free period, and a few liver tumours were seen at 2 yr. As NVP gave negative results in a battery of in vitro and in vivo genotoxicity tests, it appears that the tumours that arose were manifestations of a non-genotoxic mechanism.
No preview · Article · Oct 1997 · Food and Chemical Toxicology
[Show abstract][Hide abstract] ABSTRACT: N-Vinylpyrrolidone-2 (NVP) is a monomeric compound used as an industrial intermediate. Nine of 11 studies previously reported involved exposure of rats (two different strains), mice or hamsters to NVP by the inhalation route at concentrations of up to 120 ppm (6 hr/day, 5 days/wk) over a period of 1 wk to 12 months. The remaining two studies involved exposure of rats to NVP through the drinking water or by gavage at dose levels of up to 100 mg/kg body weight/day. Reduced body weight gain was seen in rats exposed by inhalation to 5 ppm or more for 3 months and in mice and hamsters exposed to 45 ppm for only 1 day. Effects were seen on haematological (reduced haemoglobin, erythrocyte count, haematocrit) and clinical chemistry parameters (specially raised gamma-glutamyltransferase activity and decreases in plasma protein), liver weight increase and liver lesions (centrilobular single-cell necrosis and foci of hepatocellular alteration) in rats and mice but not hamsters. Rats exposed to 40 mg/kg body weight/day NVP or more for 3 months by gavage developed similar liver changes. Atrophy of olfactory epithelium and hyperplasia of nasal respiratory epithelium was seen in rats exposed by inhalation to 5 ppm NVP for 7 wk but not in response to 1 ppm for 13 wk (no observed-adverse-effect level, NOAEL). These studies indicated that the upper respiratory tract and the liver are the main targets for NVP toxicity.
No preview · Article · Oct 1997 · Food and Chemical Toxicology