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Biomedical subjects

G L Kennedy

Publications and source records attributed to G L Kennedy.

At least 19 recordsLinked to original sources
PubMed2006

Age effect on perfluorooctanoate (PFOA) plasma concentration in post-weaning rats following oral gavage with ammonium perfluorooctanoate (APFO).

The relationship between age and plasma concentration of perfluorooctanoate (PFOA) in young rats was investigated. The study was conducted in two phases in which male and female rats between 3 and 8 weeks of age were administered the ammonium salt of PFOA (APFO) by single oral gavage at either 10 or 30mg/kg. In Phase I, APFO was administered at a dose of 10mg/kg body weight to 27-, 34-, 38-, 48-, and 55-day-old male and female rats. Plasma was collected 24h after the dose. In Phase II, APFO doses of either 10 or 30mg/kg body weight were given to groups of 23-, 30-, and 32-day-old male and female rats, and plasma was collected at 2 and 24h after the dose (separate groups), and urine was collected for 24h. PFOA concentrations were measured by LC/MS/MS. In Phase I, plasma concentrations of PFOA were not dependent on age for rats 5 weeks of age and older; however, in 4-week-old rats, male plasma PFOA concentrations were 5-6 times lower than during weeks 5-8, and female plasma PFOA concentrations were 2.5-4 times higher than subsequent weeks. In Phase II, plasma samples collected 2h post-dosing indicated no significant difference in the PFOA uptake by age in females; although, in males, plasma PFOA concentrations were significantly less in 32-day-old rats, approximating one-half of the values observed at 23 and 30 days of age. Plasma samples collected 24h after dosing from 3- to 5-week-old rats indicated a slightly but significantly higher male plasma concentration at 30 and 32 days of age as compared to 23 days of age for the 30mg/kg dose group only. Significantly lower (approximately 10-fold) plasma PFOA concentrations occurred in 32-day-old females as compared with 23- and 30-day-old females at both 2 and 24h after the dose. Although statistically significant changes in urine PFOA concentrations did not occur between age and dose groups within sex, urine PFOA concentrations generally supported plasma elimination. At 23 days of age, the ratio of male to female plasma PFOA concentrations was approximately 2-3:1 compared to approximately 30:1 at 32 days of age. An unexplainable inconsistency in PFOA plasma concentrations for both sexes was noted when comparing Phase I values for 27-day-old rats to Phase II values for 23- and 30-day-old rats. The Phase I values for the 27-day-old rats of both sexes were five to six times lower than Phase II values for the 23- and 30-day-old rats. However, Phase I values for 34-day-old rats were comparable to Phase II values for 32-day-old rats. Despite this anomaly between the 23-, 27-, and 30-day-old rat values, there is strong evidence that age-dependent changes in the elimination of PFOA develop in female rats between 3 and 5 weeks of age, with a consistent marked difference occurring after 30 days of age.

Administration, Oral↗
PubMed2006

Perfluorooctanoic acid: relationship between repeated inhalation exposures and plasma PFOA concentration in the rat.

A large database exists describing the pharmacokinetic behavior of perfluorooctanoic acid (PFOA) following oral exposure. The objective of this study was to examine the concentration- and time-dependence of the pharmacokinetics of inhaled PFOA in rat plasma to determine equivalent inhalation and oral (from literature values) exposure levels. The study was comprised of two separate experiments: a single 6-h inhalation exposure and repeated inhalation exposures for 3 weeks (6h per day, 5 days per week). In both experiments, male and female rats were exposed nose-only to aerosol atmospheres of either 0, 1, 10, or 25mg/m(3) PFOA. In the single exposure experiment, blood was drawn via the tail vein pre-exposure, four times concurrent to exposure, and six times post-exposure up to 24h. In the repeated exposure experiment, blood was collected immediately before and after exposure 3 days per week. Plasma PFOA concentrations were quantitated by liquid chromatography-mass spectrometry (LC-MS). Following the single exposures, plasma PFOA concentrations were directly proportional to airborne concentrations in both male and female rats. Elimination of PFOA from the plasma was sex-dependent, with female rats eliminating PFOA much more rapidly than male rats. Following repeated PFOA exposure, there was little daily PFOA carryover observed in plasma samples from female rats, while males demonstrated an accumulative pattern over the 3-week period. Peak post-exposure PFOA plasma concentrations in female rats averaged 1, 2, and 4 microg/mL when exposed to 1, 10, and 25mg/m(3) PFOA, respectively, and returned to baseline levels by the time of the next pre-exposure sample collection. Male rats reached steady state plasma concentrations of 8, 21, and 36 microg/mL (ppm) after 3 weeks of exposure to 1, 10, and 25mg/m(3) PFOA, respectively. These results demonstrate that the pharmacokinetic properties of inhaled PFOA in male and female rats are similar to those observed in male and female rats following oral dosing with PFOA. It is thus possible to use this internal dose metric (plasma PFOA) for route-to-route dose extrapolation, with inhalation exposures of 1, 10, and 25mg/m(3) PFOA corresponding to oral doses of approximately 0.3, 1.0, and 2.0mg/kg in rats.

Administration, Inhalation↗
PubMed2006

Absorption, distribution, and excretion of ammonium perfluorooctanoate (APFO) after oral administration to various species.

Male and female mice, rats, hamsters, and rabbits were treated with a single oral dose of 14C-ammonium perfluorooctanoate (APFO), and the excretion and tissue distributions were followed for 120 h (168 h in the rabbit). Substantial sex and species differences in the excretion and disposition of 14C-radioactivity derived from 14C-labeled APFO were observed in this study. The female rat and the male hamster excreted more than 99% of the original 14C activity by 120 h after dosing; conversely, the male rat and the female hamster excreted only 39% and 60% of the original 14C activity, respectively, by 120 h postdosing. The male and female rabbits excreted the 14C activity as rapidly and completely as the female rat and the male hamster, whereas male and female mice excreted only 21% of the original 14C activity by 120 h postdosing. The rapid excretors (female rat, male hamster, and male and female rabbits) contained negligible amounts of 14C in organs and tissues at sacrifice. The slow excretors exhibited the highest 14C concentrations in the blood and liver followed by the kidneys, lungs, and skin.

Administration, Oral↗
PubMed2006

Oral toxicity study of 2-pentenenitrile in rats with reproductive toxicity screening test.

A combined repeated-dose toxicity study with reproduction was conducted with 2-pentenenitrile (2-PN). Rats (10/sex per dose level) were dosed with 2-PN once daily by gavage at dose levels of either 0, 1, 3, or 10 mg kg(-1) day(-1) for 28 days, prior to and during cohabitation, and through day 3 of lactation. General clinical observations were recorded daily; body weights were recorded weekly. A neurobehavioral evaluation consisting of a functional observational battery and motor activity was conducted in all parental rats (10/sex per group). Clinical pathology parameters (hematology, clinical chemistry, coagulation) were measured in parental rats. Pup weights and clinical signs were recorded at birth and on lactation day 4. Parental rats were given a gross pathological examination, organ weights were obtained, and histological examination was conducted for the control and 10 mg kg(-1) day(-1) groups. No effects were seen with regard to mortality, clinical signs, functional observational battery and motor activity, hematology, or organ weights. Females receiving 10 mg/kg and males from all dose groups showed lower body weight gains and feed efficiency. Increased albumin concentrations were seen in both sexes given 10 mg/kg. Females in the 10 mg/kg group showed degeneration of the olfactory mucosa. No effects on the numbers of pups born, number surviving to lactation day 4, pup weight, and no gross anatomical development changes were observed. Under the conditions of this study, the no-observed-effect level (NOEL) for systemic toxicity in rats was 3 mg kg(-1) day(-1), based on degeneration of olfactory mucosa in females at 10 mg kg(-1) day(-1). The NOEL for reproductive and neurobehavioral toxicity in rats and for toxicity to offspring was 10 mg kg(-1) day(-1), the highest dose level tested.

Administration, Oral↗
PubMed2005

Evaluation of the developmental toxicity of 8-2 telomer B alcohol.

The potential maternal and developmental toxicity of 8-2 Telomer B Alcohol was assessed in rats. Groups of 22 time-mated female Crl:CD (SD)IGS BR rats were administered oral gavage doses as suspensions of 8-2 Telomer B Alcohol in aqueous 0.5% methylcellulose from day 6 through 20 of gestation (G) at daily doses of either 0, 50, 200, or 500 mg/kg. Under the conditions of this study, adverse maternal toxicity was produced at 500 mg kg(- 1) day(- 1) and consisted of maternal mortality, decreased body weights and body weight gains, and increased clinical observations of toxicity. One litter at 500 mg kg(- 1) day(- 1) consisted of one early resorption and was believed to be secondary to overt maternal toxicity, although single conceptus litters occur historically in this strain of rats. Developmental toxicity at 500 mg kg(- 1) day(- 1) consisted of increased fetal skeletal variations (delayed pelvic bone ossification and wavy ribs). At 200 and 500 mg kg(- 1) day(- 1), there were transient reductions in maternal feed consumption. In addition, there were slight increases in the incidence of delayed fetal skull bone ossification at 200 and 500 mg kg(- 1) day(- 1). The no-observed-adverse-effect level (NOAEL), defined as the highest dose at which adverse effects attributable to the test substance were not detected, for both maternal and developmental toxicity, is considered to be 200 mg kg(- 1) day(- 1). Thus, 8-2 Telomer B Alcohol is not considered to be a selective developmental toxicant in rats. The transient and quantitative nature of the observations in the 200 mg/kg group supports the conclusion that these findings were not adverse.

Abnormalities, Drug-Induced↗
PubMed2005

Penetration of ammonium perfluorooctanoate through rat and human skin in vitro.

Rat and human epidermal membranes were mounted onto in vitro diffusion cells with an exposure area of 0.64 cm2, and skin integrity was confirmed using electrical impedance. Following membrane selection, Fluorad FC-118, a 20% aqueous solution of ammonium perfluorooctanoate (AFPO), was applied to the epidermal surface of each skin replicate at approximately 150 microL/cm2 and the donor chamber opening occluded with Parafilm. Serial receptor fluid samples were collected hourly from 1 to 6 h and at 12, 24, 30, and 48 h and analyzed by liquid chromatography-mass spectrometry (LC-MS) for APFO anion (PFO-). For rat skin, the time to steady-state penetration (6500+/-3000 ng APFO x cm(-2) x h(-1)) occurred in less than 12 h, which was sustained until termination (48 h). Based on the concentration of the applied test material, the permeability coefficient (Kp) for APFO in rat skin was calculated to be 3.25+/-1.51 x 10(-5) cm/h. By end of the 48-h exposure period, only a small portion of the total APFO applied (1.44+/-1.13%) had penetrated through rat skin. For human skin, steady-state penetration of APFO (190+/-57 ng APFO x cm(-2) x h(-1)) was reached by 12 h. Based on the concentration of the applied test material, the permeability coefficient for APFO in human skin was calculated to be 9.49+/-2.86 x 10(-7) cm/h. By the end of the 48-h exposure period, only a negligible amount of the total APFO applied (0.048+/-0.01%) had penetrated through human skin. Thus, under infinite dose and occlusive conditions, the steady-state penetration of APFO from a 20% solution was approximately 34-fold faster through rat skin than human skin.

Animals↗
PubMed2004

Pharmacokinetics of perfluorooctanoate in cynomolgus monkeys.

The pharmacokinetics of perfluorooctanoate (PFOA) in cynomolgus monkeys were studied in a six-month oral capsule dosing study of ammonium perfluorooctanoate (APFO) and in a single-dose iv study. In the oral study, samples of serum, urine, and feces were collected every two weeks from monkeys given daily doses of either 0, 3, 10, or 20 mg APFO/kg. Steady-state was reached within four weeks in serum, urine, and feces. Serum PFOA followed first-order elimination kinetics after the last dose, with a half-life of approximately 20 days. Urine was the primary elimination route. Mean serum PFOA concentrations at steady state in the 3, 10, and 20 mg/kg-day dose groups, respectively, were 81, 99, and 156 microg/ml in serum; 53, 166, and 181 microg/ml in urine; and, 7, 28, and 50 microg/g in feces. Mean liver concentrations reached 16, 14, and 50 microg/g in the 3, 10, and 20 mg/kg groups, respectively. In the iv study, three monkeys per sex were given a single dose of 10 mg/kg potassium PFOA. Samples were collected through 123 days. The terminal half-life of PFOA in serum was 13.6, 13.7, and 35.3 days in the three male monkeys and 26.8, 29.3, and 41.7 days in the three females. Volume of distribution at steady state was 181 +/- 12 and 198 +/- 69 ml/kg for males and females, respectively. Based on the result of both the oral and iv studies, the elimination half-life is approximately 14-42 days, and urine is the primary route of excretion.

Animals↗
PubMed2003

Inhalation toxicity of dimethyl piperidinone.

A mixture of 1,3-dimethyl-2-piperidinone and 1,5-dimethyl-2-piperidinone (DMPD) (approximately 63-37 parts by weight) was tested for its inhalation toxicity in rats following 90-day repeated exposures. Male and female rats were exposed whole-body to either 0, 51, 230, or 310 mg/m(3) DMPD for 6 h/day, 5 days/weak for 90 days. Clinical signs, growth, clinical pathology, tissue pathology, neurobehavior, neuropathology, and semen quality were evaluated. No compound-related adverse effects were noted in clinical signs, body weights, food consumption, clinical laboratory evaluations, neurobehavioral evaluations, neuropathology, or sperm counts. Laryngeal changes consisting of minimal squamous epithelial hyperplasia and degeneration/necrosis of the cartilage were present in male and female rats exposed to 310 mg/m(3) both immediately following exposure and after the 1-month recovery period Male rats exposed to DMPD had increased relative kidney weights, increased formation of hyaline droplets and granular casts, and increased incidence of chronic progressive nephropathy. These kidney effects are consistent with increased accumulation of the urinary protein alpha(2 mu)-globulin, which has been well essential for several xenobiotics. The subsequent increased incidence of progressive nephropathy was specific to male rats with the alpha(2 mu) syndrome. Male and female rats exposed to 230 or 310 mg/m(3) had centrilobular hepatocellular hypertrophy, and male rats exposed to 310 mg/m(3) had increased relative liver weights. These liver changes were reversible following the recovery period and were considered not to represent adverse toxicological effects of treatment. Since the male rat-specific renal findings do not connote adversity for man and are net considered relevant to human hazard assessment, the no-observed-effect level in male and female rats was 230 mg/m(3), based on the microscopic changes in the larynx exposed to 310 mg/m(3).

Animals↗
PubMed2003

Inhalation toxicity of methylglutaronitrile in rats.

Methylglutaronitrile (MGN) is a high-boiling (263 degrees C) solvent/intermediate used in the fiber industry. Twenty male rats per group were exposed nose-only to condensation aerosol/vapor concentrations of approximately either 5, 25, or 200 mg/m3 of MGN for 6 h/day, 5 days/week over a 4-week period. Ten rats/group were sacrificed one day after the final exposure and the remaining rats after a four-week recovery period. No effects were observed in clinical observations during the exposure period, but body-weight depression was observed in the 200 mg/m3 group. The 200 mg/m3 group showed minimal decreases in red blood cell count, hemoglobin, and hematocrit values accompanied by increases in reticulocytes. There were no other effects observed in clinical or pathologic evaluations in the study. A neurobehavioral battery of tests (including grip strength, functional observational battery, and motor activity tests) given at the end of the exposure and recovery periods showed no MGN effects. During the 4-week recovery, body weights in the 200 mg/m3 group returned to normal and the hematologic findings in all groups were normal. Based on the above findings of body weight depression at 200 mg/m3, the no-observed-adverse-effect level (NOAEL) for this study was considered to be 25 mg/m3.

Administration, Inhalation↗
PubMed2003

Evaluation of the potential developmental toxicity of cyclododecatriene (CDDT).

The potential maternal and developmental toxicity of cyclododecatriene (CDDT) was assessed in rats. Groups of 22 time-mated female Crl:CD (SD) BR rats were exposed by inhalation (whole-body, 6 h/day) to either 0 (control), 10, 25, or 67 ppm CDDT over days 6-20 of gestation (days 6-20 G); the day of copulation plug detection was designated day 0 G. The dams were euthanized on day 21 G, and their abdominal and thoracic viscera were examined grossly. The fetuses were weighed, sexed, and examined for external, visceral, and skeletal alterations. Evidence of maternal toxicity was seen at 25 and 67 ppm. There were compound-related reductions in maternal body weight and food consumption parameters as well as increased occurrences of wet and stained fur at these exposure levels. Developmental toxicity evident as reduced mean fetal weight and delayed skeletal ossification was seen only at 67 ppm. There was no evidence of either maternal or developmental toxicity at 10 ppm. Thus, the no-observed-effect level (NOEL) for maternal toxicity was 10 ppm, and the NOEL for developmental toxicity was 25 ppm. Because developmental toxicity was observed only after exposures that also produced signs of maternal toxicity, CDDT was not considered to be a selective developmental toxicant in the rat.

Abnormalities, Drug-Induced↗
PubMed2002

Initial study in rats evaluating the effects of 1,4-dichlorobutene-2 (DCB) on the respiratory tract.

Rats were exposed by inhalation to either 0.5 ppm 1,4-dichlorobutene-2 (DCB) for two years or to 5.0 ppm for seven months, 2.5 ppm for five months, and no further exposure for 12 months prior to sacrifice. Malignant and non-malignant tumors of the nasal tissues were seen in both test groups with the incidence and proportion of malignant tumors being much higher in the 5.0/2.5 ppm rats. Under the conditions of this study, DCB is carcinogenic in rats of both sexes.

Administration, Inhalation↗
PubMed2001

Absorption of dimethylacetamide (DMAC) following application of a polymer film to the skin of rabbits.

Kapton Film is a polymer with high strength and thermal resistance finding use in a wide variety of applications. In the preparation of this film, the uncured material could contain up to 30% dimethylacetamide (DMAC). Note that the final product Kapton Film has been thermally cured with the DMAC removed. During processing, dermal contact with the film is anticipated, and the possibility exists of DMAC transfer from the uncured film, to and through the skin. In this study, 2 x 2-inch pieces of film were applied to the skin of a group of rabbits and secured in place for a single 4-hour contact time. An amount of liquid DMAC corresponding to the amount contained in the 2-inch square was applied to the skin of a separate group of rabbits for 4 hours. Urine samples were collected over the intervals of application to 4 hours post application (8 hours total) or 4 to 20 hours post application (16 hours). The amount of the urinary metabolite monomethylacetamide (MMAC) was determined analytically in these samples. Urine from 2 untreated rabbits was collected at the same time to serve as controls. The amount of urinary MMAC found in the rabbit rine from animals exposed to uncured Kapton Film at both ollection intervals was similar to the amount seen in the controls (background). Rabbits treated with DMAC liquid had measurable urinary MMAC levels that were approximately 100 times background. It is concluded that, under the conditions of this study, very little, if any, DMAC from the uncured Kapton Film was absorbed through the skin (and excreted in the urine as MMAC).

Acetamides↗
PubMed2001

Potential pulmonary effects of man-made organic fiber (MMOF) dusts.

In the first half of the twentieth century epidemiologic evidence linked elevated incidences of pulmonary fibrosis and cancer with inhalation of chrysotile and crocidolite asbestos, a family of naturally occurring inorganic fibrous materials. As the serpentine and amphibole forms of asbestos were phased out, synthetic vitreous fibers (SVFs; fiber glass, mineral wool, and refractory fiber) became increasingly utilized, and concerns were raised that they too might cause adverse health effects. Extensive toxicological research on SVFs has demonstrated that their pulmonary effects are directly related to fiber dose in the lung over time. This is the result of deposition (thin fibers deposit in the lower lung more efficiently than thick fibers) and lung-persistence ("biopersistence" is directly related to fiber length and inversely related to dissolution and fragmentation rates). In rat inhalation studies, asbestos was determined to be 7- to 10-fold more biopersistent in the lung than SVFs. Other than its effect on biopersistence, fiber composition did not appear to play a direct role in the biological activity of SVFs. Recently, the utilization of man-made organic fibers (MMOFs) (also referred to by some as synthetic organic fibers) has increased rapidly for a variety of applications. In contrast to SVFs, research on the potential pulmonary effects of MMOFs is relatively limited, because traditionally MMOFs were manufactured in diameters too thick to be respirable (inhalable into the lower lung). However, new developments in the MMOF industry have resulted in the production of increasingly fine-diameter fibers for special applications, and certain post-manufacturing processes (e.g., chopping) generate respirable-sized MMOF dust. Until the mid-1990s, there was no consistent evidence of human health affects attributed to occupational exposure to MMOFs. Very recently, however, a unique form of interstitial lung disease has been reported in nylon flock workers in three different plants, and respirable-sized nylon shreds (including fibers) were identified in workplace air samples. Whether nylon dust or other occupational exposures are responsible for the development of lung disease in these workers remains to be determined. It is also unknown whether the biological mechanisms that determine the respirability and toxicity of SVFs apply to MMOFs. Thus, it is appropriate and timely to review the current data regarding MMOF workplace exposure and pulmonary health effects, including the database on epidemiological, exposure assessment, and toxicology studies.

Administration, Inhalation↗
PubMed2001

Repeated exposure inhalation study of pentane in rats.

Pentane (CAS No. 109-66-0) is a chemical being used as a co-solvent in a polymer production facility with potential for inhalation exposure in humans. To assess the toxicity of pentane, groups of 10 male rats each were exposed by inhalation, 6 hr/day, 5 days/week for 2 weeks to either 0 (control), 1,000, 3,000 or 10,000 ppm. Five rats per group were killed following the 10th exposure; the remaining 5/group were killed after a 14-day post-exposure recovery period. Parameters investigated were clinical signs of toxicity, functional behavior, body weights, clinical pathology, and gross and microscopic pathology including organ weights. No unusual clinical observations were seen in the pentane-treated rats, and body weights were not altered. Test rats generally exhibited normal behavioral responses in the functional observational battery. Increases in serum calcium and phosphorus concentrations were seen in rats exposed to either 3,000 or 10,000 ppm. These were reversible during the 2-week recovery period. No other clinical pathology changes were observed and no pentane-related tissue pathology was seen in any of the groups. The no-observed-adverse-effect level was 1,000 ppm with reversible clinical pathology changes produced at 3,000 and 10,000 ppm.

Administration, Inhalation↗
PubMed2001

Evaluation of the potential developmental toxicity of 3-aminopentanenitrile (3-APN) in the rat.

The potential developmental toxicity of 3-aminopentanenitrile (3-APN) was assessed in rats. Groups of 25 time-mated female Crl:CD(SD)IGS BR rats were orally gavaged at daily dose levels of 0, 5, 30, 100 or 300 mg/kg over days 6-20 of gestation (days 6-20G); the day of copulation plug detection was designated day 0G. The dams were euthanized on day 21G and their abdominal and thoracic viscera were examined grossly. The fetuses were weighed, sexed, and examined for external, visceral, and skeletal alterations. Evidence of maternal and developmental toxicity was seen at 100 and 300 mg/kg. Regarding maternal toxicity, there were compound-related, statistically significant reductions in maternal body weight and food consumption at 100 and 300 mg/kg. The incidence of alopecia was significantly increased at these levels as well. Regarding developmental toxicity, mean fetal weight was slightly but significantly reduced at 100 and 300 mg/kg. In addition, at 300 mg/kg, there were significant increases in several skeletal variations (wavy ribs and skull, rib, and vertebral ossification delays) consistent with developmental delay. There was no evidence of either maternal or developmental toxicity at 5 or 30 mg/kg. Thus, the maternal and developmental no-observed-effect level (NOEL) was 30 mg/kg. Because developmental toxicity was observed only after administration of doses that also produced signs of maternal toxicity, 3-APN is not considered to be a selective developmental toxicant in the rat.

Animals↗
PubMed2001

Inhalation toxicity of Dioxole and Dioxolane compounds in the rat.

Four chemicals (Dioxole 418, Dioxolane 418, Dioxolane 416 and Dioxolane 456) which are used as stabilizers in highresolution image were tested or both their acute and repeated inhalation toxicity in the rat using nose-only exposures. Acute studies determined the lethal concentrations following a single 4-hour exposure; repeated exposure inhalation studies determined the potency and target tissue(s) following 6-hour/day exposures, 5 days/week for 2 weeks. Each of the chemicals was at least mildly toxic acutely with approximate lethal concentrations of > 1,500 ppm for Dioxole 418, 1,300 ppm for Dioxolane 418, 1,700 ppm for Dioxolane 416, and 4,300 ppm for Dioxolane 456. No specific unusual clinical signs of response were seen in the rats exposed acutely. Repeated exposures with Dioxole 418 and Dioxolane 418 resulted in no evidence of toxicity with NOAEL's being 440 and 500 ppm respectively (the highest concentrations tested). Repeated exposures to 250 ppm Dioxolane 456 were not tolerated with mortalities observed after exposure. Severe bone marrow hypoplasia along with reductions in platelet and neutrophil counts were observed at this concentration with less severe hemopoietic changes seen also at 10 and 51 ppm. The no-effect level for Dioxolane 456 was determined to be 10 ppm in female rats and I ppm in males. The same hemopoietic effects were seen with Dioxolane 416 at exposures of 53 ppm or greater in males but not in females exposed to 53 ppm Dioxolane 416. Hepatocellular hypertrophy and depression of serum alkaline phosphatase activity were seen in male rats exposed to 500 but not 53 ppm Dioxolane 416. Testicular degeneration was also seen in rats exposed to 500 ppm Dioxolane 416. The NOAEL was 5 ppm for the chemical.

Administration, Inhalation↗
PubMed2001

Inhalation toxicity of cyclooctadiene in rats.

Groups of 20 male Crl:CDBR rats each were exposed, whole-body, for six hours/day, for a total of nine exposures over a two-week period to concentrations of 52, 150, or 500 ppm of 1,5-cyclooctadiene vapor. A control group of 20 male rats was exposed simultaneously to houseline air. Ten rats per group were used for standard toxicological evaluations and ten rats per group for neurotoxicity testing. In the standard toxicology group, at the end of the exposure period, blood and urine samples were collected for clinical analyses, and five rats per group were sacrificed for pathologic examination. After a two-week recovery period, the surviving rats in the standard groups were also given clinical and pathological examinations. The neurotoxicity group was given a functional observational battery (FOB) test and motor activity evaluations after the fourth and ninth exposures. In addition, six of ten neurotoxicity rats per exposure group were given neuropathology evaluations at the end of the exposure period. In rats exposed to 500 ppm of 1,5-cyclooctadiene there was an absence of alerting response toward the end of the daily six-hour exposures. These rats appeared to recover within 1/2 hour after exposure. This effect was not observed in the other test groups. The FOB evaluation showed an increase in the number of rats found sleeping in the 500 and 150 ppm groups compared to controls after the last exposure, but there were no treatment-related effects in the motor activity evaluation. Since there were no other neurobehavioral findings and no toxicity findings in the 150 ppm group, the sleeping behavior in the 150 ppm group was considered insufficient evidence of an adverse effect. Clinical laboratory evaluation of the 500 ppm group showed urinary pH decreases at the end of the exposure period but not after the two-week recovery period. There were no other toxicologically important changes in urine analysis, hematologic, or blood chemistry evaluations attributable to the test compound. Histologic effects were found in the nose and kidneys of rats in the 500 ppm group. There was a mild degeneration/necrosis of nasal olfactory epithelium observed immediately after the exposure period and a mild degeneration/regeneration in this area observed after the two-week recovery. In addition, there were increased kidney weights in the 500 ppm group immediately after exposure along with increased hyaline droplets in the kidneys. These effects were reversible after the two-week recovery period. There were no significant nasal or kidney effects observed in the 150 and 52 ppm test groups, and no other organ weight or histological effects attributable to the test compound observed in the standard toxicology groups at either evaluation time. The neuropathologic evaluation showed only one minor lesion in one 500 ppm-group rat and this was not considered to be attributable to exposure to 1,5-cyclooctadiene. Based on the decreased alerting response observed in rats during exposure at 500 ppm, and on the effects observed in the nose, kidney, and urine in rats at this concentration, the no-observed-adverse-effect (NOAEL) level in this study was considered to be 150 ppm.

Administration, Inhalation↗