Abstract  Cyclotrimethylenetrinitramine (RDX) has been used extensively as an explosive. Prior to this study no data were available on the metabolism of RDX in animals. Metabolism of 14C-RDX was studied in male and female miniature pigs after a one-time gavage with 41 to 44 mg/kg, (0.8 to 0.9 mCi/animal) in an aqueous suspension of 0.1% carboxymethyl cellulose. Metabolic profiles and identification of 14C-RDX-derived radioactivity in plasma, liver and urine were performed utilizing HPLC radio-scanning and LC/MS/MS analysis. Analytical standards were available for all proposed metabolites. Two HPLC columns with differing elution profiles were used for separation, quantification and tentative identification. Identifications were confirmed using LC/MS/MS. Two metabolites were isolated and identified as 4-nitro-2, 4-diazabutanal and a novel metabolite, 4-nitro- 2-4 diaza-butanamide. Analysis also revealed trace levels of 1-nitroso-3,5-dinitro-1,3,5-triazacyclohexane (MNX), 1,3-dintroso-5-nitro-1,3,5-triazacyclohexane (DNX) and 1,3,5-trinitroso- 1,3,5-triazacyclohexane (TNX) in plasma and showed trace levels of MNX and DNX in urine. No metabolites were detected in the liver samples. Thus RDX was metabolized primarily by a method that accomplished both denitration and oxidative cleavage of the ring structure of this compound to form butanal and butanamide metabolites.

Abstract  The toxicity, tissue distribution, and metabolism of cyclotrimethylenetrinitramine (RDX) have been studied. Yet, little information is available on morphological changes that might be attributed to it. Because RDX is a potential occupational or environmental contaminant, such information is necessary for the overall evaluation of RDX toxicity. The ultrastructure of rat liver and kidney was examined 24, 48 and 120 hr after dosing with 100 mg of RDX/kg po. Conventional transmission electron micrographs revealed hepatocytes with dilation of the rough endoplasmic reticulum, mit ochondrial swelling, and the presence of concentric membrane arrays 24 hr after RDX administration. Renal ultrastructural alteration was apparently restricted to the distal convoluted tubular cells. No consistent variation in ultrastructure was observed in glomerular cells, proximal convoluted tubular cells, and collecting tubular cells. The presence of erythrocytes in the nephron tubules indicated hematuria. By 48 hr, hepatocyte alteration was similar and of the same magnitude, except for the proliferation of smooth endoplasmic reticulum (SER). No consistent effects were observed on renal ultrastructure at 48 or 120 hr. At 120 hr, the characteristic hepatocyte alterations as described above persisted

Abstract  A number of compounds present in wastewater from munitions plants were examined before an dafter ozonation of chlorination to dermine whether any were mutagenic before treatment and whether such activity was affected by the treatment. Several photolytic as well as metabolic products of trinitrotoluene (TNT) also were examined for mutagenic activity. Test materials included TNT, TNT production wastewater, and individual components of TNT wastewater (1,3-dinitrobenzene; 2,4-dinitrotoluene; 3,5-dinitrotoluene; hexahydro-1,3,5-trinitro-s-triazine (RDX); octahydro-1,3,5,7-tetranitro-s-tetrazine (HMX); components of photolysed TNT; pentaerythritol tetranitrate (PETN); and trinitroresorcinol. The in vitro mutagenic assays used were the Ames Salmonella/microsome assay (strains TA1535, TA1537, TA1538, TA98, and TA100) and mitotic recobination in the yeast, Saccharomyces cerevisiae D3. A metabolic activation system using the posmitochondrial supernatant fraction of liver from rats pretreated with Aroclor 1254 was included in each assay procedure. Materials found to be mutagenic prior to and after treatment were trinitrobenzene, trinitrobenzaldehyde, trinitrobenzonitrile, and 50 and 100% photolysed TNT wastewater. Neither ozonation nor chlorination significantly altered the mutagenic activity of the materials tested.

Abstract  We hypothesized that CYP3A N -dealkylation of alachlor is a key determinant in hepatocyte cytotoxicity and that such metabolism has relevance to human hepatotoxicity. Results show that highly N -dealkylated chloroacetanilides alachlor and acetochlor were potent cytotoxicants compared to negligible N -dealkylated metolachlor to Sprague-Dawley (SD) rat hepatocytes (NRH). Higher cytotoxicity of N -dealkylated alachlor metabolite CDEPA in NRH suggests that N -dealkylation is a bioactivation process. Sensitization to alachlor cytotoxicity in hepatocytes from dexamethasone-pretreated rats (DRH), and lower alachlor cytotoxicity with a potent CYP3A inhibitor (clotrimazole) correlated with the rate of CDEPA formation supports a critical role of CYP3A N -dealkylation. In contrast, alachlor cytotoxicity in cryopreserved human hepatocytes is inversely correlated with CYP3A4 indicating its involvement in detoxication. Further, comparable cytotoxicity of alachlor, acetochlor, and metolachlor suggests species-specific mechanisms of toxicity for these chloroacetanilides with a greater relative risk of adverse effects from metolachlor in humans than predicted from rat studies. RDX (hexahydro-1,3,5-trinitro-1,3,5-trazine) is widely used munitions compound and now contaminate soil and ground water at artillery training and manufacturing sites. RDX is anaerobically degraded to mono di and tri N -nitroso products MNX, DNX and TNX, respectively. MNX is the most potent of three degradation products in-terms of LD 50 and anemia. We hypothesized that transformation of RDX to MNX decreases hematotoxicity. Results are obtained from studies conducted using female SD rats indicate that 14-day acute oral exposure to RDX and MNX resulted in anemia (NOAEL 47 mg/kg). RDX was more potent than MNX in decreasing peripheral blood leukocytes and bone marrow cellularity. RDX and MNX were found to decrease Burst Forming Units-Erythroblasts (BFU-E, NOAEL 12 mg/kg) and Granulocyte Macrophage-Colony Forming Units (CFU-GM, NOAEL < 12 mg/kg) 14 days after exposure. Stimulation of the Colony Forming Units-Granulocyte, Erythrocyte, Monocyte, Macrophage (CFU-GEMM) at lower doses and no effects with CFU-GM and BFU-E were observed after 7-day acute exposure. Flow cytometry analysis revealed no change in cell surface expression CD71 and Thy1.1 markers. In conclusion, reduction of RDX to MNX is a detoxification process and may affect growth of a relatively proximal committed stem cell population in hematopoiesis.

Abstract  The genotoxicity of energetic compounds that commonly occur in contaminated soils at military training sites has not been rigorously tested. The Salmonella and Muta T Mouse in vitro mutagenicity assays were employed to examine the mutagenic activity of selected energetic compounds including TNT, tetryl, RDX, and HMX, as well as explosives-contaminated soil samples. Salmonella analyses employed strains TA98 (frameshift), TA100 (base-pair substitution), and the metabolically enhanced YG 1041, with and without exogenous metabolic activation (S9). Results indicate that TNT is a direct-acting mutagen, eliciting significant responses without S9. Strains TA98, TA100, and YG1041 yielded mutagenic potencies of 0.87±0.03, 1.72±0.08, and 1.32±0.06 revertants/IJg TNT, respectively. In contrast, tetryl elicited significant responses both with and without S9, exhibiting mutagenic activity in all strains. Potencies ranged from 1.27±0.13 to 14.98±1.67 revertants/IJg tetryl. Testing of soil samples yielded significant responses in strains TA98 and YG1 041, with and without S9. Mutagenic potencies ranged from 3.48±0.13 to 16.20±0.97 revertants/mg soil equivalent. Responses obtained using the Muta ™Mouse assay in FE 1 cells indicate that TNT can induce lacZ mutations, with and without S9. In contrast, there is little evidence to support the mutagenic activity of tetryl or RDX. HMX appears to be toxic to FE1 cells. Testing of soil samples in the Muta™Mouse assay is currently underway. Analysis of other energetic compounds and contaminated soil samples is warranted in order to reliably estimate mutagenic hazard.

Abstract  This statement was prepared to give you information about RDX and to emphasize the human health effects that may result from exposure to it. The Environmental Protection Agency (EPA) has identified 1,397 hazardous waste sites as the most serious in the nation. These sites make up the National Priorities List (NPL) and are the sites targeted for long-term federal clean-up activities. RDX has been found in at least 16 of the sites on the NPL. However, the number of NPL sites evaluated for RDX is not known. As EPA evaluates more sites, the number of sites at which RDX is found may increase. This information is important because exposure to RDX may cause harmful health effects and because these sites are potential or actual sources of human exposure to RDX.

Abstract  Given the potent carcinogenic effects of most N-nitroso compds., the reductive transformation of the common explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to a group of N-nitroso derivs., hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX) and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) in the environment have caused concerns among the general public. Questions are arising about whether the same transformations also occur in mammals and, if true, to what extent. This study investigated the N-nitroso derivs. prodn. in the deer mice GI tract following RDX administration. The findings verified that such transformations do occur in the mammalian GI tract at notable levels: the av. MNX concns. in deer mice stomach were 85 ng/g and 1,318 ng/g for exposure to 10 mg/kg and 100 mg/kg diet, resp. DNX in stomach were 217 and 498 ng/g for 10 mg/kg and 100 mg/kg dietary exposure, resp. Changes in other toxic endpoints including body wt. gains, food consumptions, organ wts. and behaviors were also reported.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM MEETING ABSTRACT VICIA TRINITROTOLUENE HEXOGEN NITROGLYCERIN

Abstract  Cyclotrimethyl trinitramine (RDX), a military explosive, has been extensively used by the U.S. Military since the late 1930’s. Military bases across the United States have been contaminated due to the testing and disposal of RDX, along with other explosive compounds. Due to this contamination, human exposure is possible both during remediation processes and through groundwater contamination. RDX has been reported to cause convulsions in military field personnel who ingest it and in munition workers inhaling its dust during manufacture. The current oral Reference Dose (RfD) was derived from a rodent chronic feeding study on military grade RDX commissioned by the U.S. Army (Levine et al 1983). The No Observed Adverse Effect Level (NOAEL) for this study was reported to be 0.3 mg/kg/day, based on prostate inflammation. In order to refine the reported NOAEL, which will be used to establish cleanup levels for contaminated sites, a subchronic study in Fischer 344 rats was performed using pure (99.9%) RDX administered via oral gavage. For dosing purposes, the RDX was suspended in a solution of 1% Methyl Cellulose and 0.2% Tween 80 in distilled water. Male and female Fischer 344 rats were dosed seven days per week for ninety days at dose levels of 0, 4, 8, 10, 12, and 15 mg/kg/day. Dosage levels were based on the results of an Approximate Lethal Dose Procedure and a 14-day repeated dose study performed prior to the subchronic study. RDX produced neurotoxic signs (tremors, seizures), as well as significant differences in body weights and food consumption, in the 8, 10, 12, and 15 mg/kg/day dose groups of both male and female rats. Death was observed in all dose groups above 4 mg/kg/day. Based on the results of this study, the NOAEL is 4 mg/kg/day.

Abstract  The objective of this study was to evaluate the toxicity of munitions compounds that find their way into wastewaters at Army ammunition plants. Rats and mice were fed TNT (2,4,6-trinitrotoluene) or TNT/RDX (TNT/1,3,5-trinitrohexahydro-1,3,5-triazine) 1.6/l mixtures in their diet for 90 days. Dogs were dosed daily by capsule with TNT or the TNT/RDX mixture for 90 days. The TNT/RDX 1.6/l mixture is representative of untreated wastewaters from Army ammunition plants conducting load, assemble, and pack operations. During the treatment period, the highest dose rats and mice (0.25 and 0.125% TNT in the diet, respectively, and 0.5% TNT/RDX for both species) exhibited weight loss, reduced food intake, and red urine. Dogs on the highest dose (20 mg/kg/day of TNT or 50 mg/kg/day of TNT/RDX mixture) exhibited weight loss, ataxia, nystagmus, and other neurological signs, as well as an orange urine. Hematological changes in all three species (high dose only) included a reduced red cell count, reduced hemoglobin, hematocrit, and an increased red cell volume with increased numbers of reticulocytes. Clinical chemistry changes included increased cholesterol and decreased SGPT activity in rats and dogs. Histopathological findings included hemosiderosis of the spleen, and sometimes the liver, in all three species receiving the highest doses. Testicular atrophy with focal interstitial cell hyperplasia was seen in the rats receiving 0.25% TNT diets.This was also seen in rats receiving 0.5% TNT/RDX and dogs receiving 50 mg/kg/day of TNT/RDX. Female rats receiving 0.5% TNT/RDX were found to have a hypoplasia of the uterus. No-effect levels of TNT in the diets of rats and mice were 0.01% and 0.005%; for TNT/RDX, these values were 0.005% and 0.005%, respectively. In dogs, the no-effect level was 0.2 mg/kg/day for TNT and 0.5 mg/kg/day for TNT/RDX. In general, the TNT content of the mixture was dominant in producing toxicity. (Supported by the U.S. Army Medical Research and Development Command, under Contract No. DAMD 17-76-C-6050.)

Abstract  Of nine nitroaromatic explosives tested, seven have moderate to strong mutagenic activity. Included in this group is 2,4,6-trinitrotoluene (TNT), the most widely used military explosive. Most of these compounds act as direct-acting, frameshift mutagens in the Ames Salmonella test system. An exception is tetryl (N,2,4,6-tetranitro-N-methylaniline) a military booster explosive. While this compound is also a direct acting mutagen (in Salmonella, Saccharomyces and Neurospora) it causes only base-pair substitution mutations.

Abstract  Translation of article appearing in Farmakologiia i Toksikologiia.

Abstract  The objective of this study was to assess the subchronic (subacute) toxicity of RDX to adult zebrafish. Mixed-sex populations of 3-month-old, young adult fish were exposed to measured RDX concentrations of 0, 1 and 9.6 mg/L for up to 12 weeks followed by a 15-day recovery in clean water. At 9.6 mg/L, RDX induced a cumulative mortality rate of about 45 percent over the 12-week exposure, with most mortalities occurring within the first 4 weeks and becoming negligible after 8 weeks. Fish held at 9.6 mg/L also showed abnormal feeding behavior during the first 8 weeks of exposure; and somatic measurements indicated that RDX at 9.6 mg/L suppressed body weight at 4 and 8 weeks of exposure and at 1 mg/L, it suppressed body weight at 4 weeks. However, the effects of RDX at 9.6 mg/L on feeding behavior were no longer evident after 8 weeks of exposure, and these fish regained normal weight by the end of the 12-week exposure period relative to control fish. Histopathological analyses of gonads from fish collected at 12 weeks of exposure did not reveal structural abnormalities. In males, Comet assay of dispersed testicular cells taken at the completion of the exposure period did not indicate the presence of DNA strand breakages related to RDX exposure. RDX and its metabolite, MNX, were detected at 4, 8, and 12 weeks of RDX exposure. The bioconcentration factor for RDX was affected by time of exposure but not by RDX concentration; average combined values were <= 1 at 4 and 8 weeks of exposure and 2 at 12 weeks. RDX and MNX were not detected in fish after a recovery period of 15 days in clean water. The latter observation suggests that RDX and MNX are readily eliminated from the fish.

Abstract  We determined the influence of sample storage time on the percutaneous absorption of C-14 labeled hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (RDX), 2, 6-dinitrotoluene (26DNT) and 2, 4, 6-trinitrotoluene (TNT) from two' soil types, Yolo having 1.9% carbon and Tinker having 9.5% carbon content. RDX soil samples stored at -20C for 27 months and 62 months were compared to freshly spiked soil samples. Similarly, 26DNT samples stored 35-36 months and TNT samples stored 18 months were compared to freshly spiked samples. Approximately 10 ug/cm2 of radio labeled compound was applied in 10 mg/ cm2 of soil to freshly excised pig skin pretreated with artifical sweat (5 ul) and mounted in skin penetration-evaporation chambers, Radiolabel recovered from the dermis and tissue culture media (receptor fluid) was summed to determine percent absorption from the soils. For each compound, percent absorptions of label were highest from Yolo soil. Storage did not significantly alter percutaneous absorption values for RDX, as values were all less than 1%, regardless of soil type or age. Similarly, 26DNT absorption was 1-2% for Tinker soil and 16-18% for Yolo soil, regardless of soil age. TNT absorption was approximately 0.5% from Tinker soil and 3-4% from Yolo soil for fresh and stored samples. HPLC analysis of26DNT in receptor fluid at maximum flux indicated no metabolism or breakdown. For TNT, extensive conversion to monoarnino derivaties and other metabolites was observed. The absorption of 26DNT from low carbon soil was reduced from 16-J 8% to near zero without sweat pretreatment, indicating that skin surface moisture was a critical variable in determining topical bioavailability.

Abstract  Cyclotrimethylenetrinitramine (RDX), a nitramine compound, has been used extensively as an explosive in military munitions since World War II. The toxicokinetic data in animals are limited. In this study, the toxicokinetics of 14C-RDX-derived radioactivity was examined following administration of a single oral dose formulated as an aqueous suspension in 0.1% carboxymethylcellulose at a target dose level of 43 mg/kg (53 μCi/kg) to male and female Yucatan minipigs. Blood was collected at 1, 6, 12 and 24 hours postdose from each animal. Urine and feces were collected through 24 hours postdose. Animals were sacrificed at 24 hours postdose and selected tissues collected. Blood, plasma, tissues, and excreta were analyzed for total radioactivity. Female minipigs vomited and experienced tremors and convulsions within 1 hour postdose. Only vomiting was observed in male minipigs, occurring within 2 hours postdose. Animals appeared normal by 2.5 hours postdose. Urine was the major route for elimination of 14C-RDX-derived radioactivity, with 17.3 and 17.6% of the radioactive dose, respectively, in males and females. RDX was well absorbed. Feces accounted for less than 1% of administered dose and gastrointestinal contents for about 5.6% of the dose. The distribution of 14C-RDXderived radioactivity was extensive, with radioactivity observed in all collected tissues. The highest concentrations of radioactivity were observed in liver and kidney. The calculated percent of radioactive dose was high in liver (3.5 to 5.8%) and muscle (2.5 to 4.7%). Profiling and metabolite identification in urine, plasma, and selected tissues are in progress.

Abstract  Dermal exposure of RDX and other nitroaromatics is a major concern for the military. There is no information on dermal absorption of RDX in humans for risk assessment. We studied dermal absorption of RDX in human skin in vitro in flow-through diffusion cells. RDX (38.46 microg/0.5 microCi) in acetone (10 microl) was applied to the skin and collected as diffused receptor fluid for every 6 hr up to 24 hrs. The unabsorbed RDX was washed with soap water and water with cotton swabs, and radioactivity present in washings was determined. The RDX absorbed or penetrated in the skin was also determined by separating stratum corneum, epidermis and dermis at the end of the experiments.

Abstract  This study involves the mutagenicity of 2,4,6-trinitrotoluene (TNT), hexogen (RDX) and nitroglycerin (NG) detected by Vicia root-MCN and the mutagenicity of TNT, RDX and NG workshop air. The results indicate that the above three chemicals all have mutagenicity. The maxima micronucleus frequencies are in the dose of 50 mg/l, 100mg/l and 5 mg/l, respectively. These three chemicals workshops air all have mutagenicity also. The maxima micronucleus frequencies are in the dose of 3.7 mg/m3, 1.11 mg/m3, and 0.11 mg/m3, respectively. (In this study, these three chemicals dose ranges are: TNT: from 0.12-3.73 mg/m3, RDX: from 0.66-1.11 mg/m3, NG: from 0.11-3.53 mg/m3).