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PubMed1975

A review of bromine determination in foods.

Organic compounds containing bromine, including methyl bromide, ethylene dibromide, and 1,2-dibromo-3-chloropropane, have been used extensively for the fumigation of foods, or soils in which foods grow, making it necessary to determine residues of bromine and bromine-containing organic compounds. A large number of methods for the determination of bromine in foods, as organic, inorganic, and combined total bromide, have been developed. In methods for organic bromide, the bromine is converted to the inorganic form for measurement by titration, photometry, or other means. In recent years, instrumental methods have been developed in which the total bromine in the sample is determined, regardless of the state in which it exists. X-ray fluorescence and neutron activation analysis are the 2 instrumental methods used most widely. Residue data are presented for some typical bromine-containing samples.

Activation Analysis↗
PubMed2001

[A case of chronic methyl bromide intoxication showing symmetrical lesions in the basal ganglia and brain stem on magnetic resonance imaging].

A 30-year-old man developed paresthesia in the feet, unstable gait and blepharoptosis subsequent to pharyngeal pain while working in a warehouse of imported fruit and vegetable fumigated with methyl bromide and cyanate. Neurological examination showed bilateral blepharoptosis, diplopia, ataxic gait and paresthesia below the inguinal region. The serum concentration of thiociane, a metabolite of cyanide, was within normal limits, but that of bromide was elevated (43.7 mg/l, normal: 3.7-8.6). Thus we diagnosed the patient as intoxication of methyl bromide. Magnetic resonance imaging of the brain (MRI) revealed bilateral symmetrical lesions of high signal intensity in the posterior region of the putamen, the subthalamic nuclei, the dorsal medulla oblongata corresponding to inferior cerebellar peduncles and vestibular nuclei, the inferior colliculi and the periaqueductal gray matter surrounding the oculomotor nucleus of the midbrain. As far as we know, this is the first report of MRI detected cerebral lesions in a case with intoxication of methyl bromide.

Adult↗
PubMedDate not supplied

[The community and the control of Aedes aegypti: perception and behavior regarding temephos larvicide].

Given the persistence of Aedes aegypti foci in the Santiago de Cuba municipality in 1998, a survey was made among the dwellers of the houses to find out their acceptance and behaviour in relation with temephos, to precise over the reasons why the product was not kept in water containers and to know the aspects associated with the existence of foci and their control. It was found that there were filled water tanks in houses where there was daily water supply so that dirt can deposit and water be used later. In 72.2% of the houses, water tanks were washed and refilled every 4 day approximately. It was concluded that water dirtiness was an additional factor to keep water in tanks, the use of temephos(abate) in water tanks for domestic use did not meet the objective pursued by this larvicide, the role of fumigation was overvalued and lack of appropriate knowledge may influence the behaviour of these surveyed persons.

Aedes↗
PubMed2002

[Herbicides and congenital malformations in Meta, Colombia].

In this paper is presented an statistical study realized upon the duplicated rate of congenital malformations per 100,000 inhabitants observed in the district of Meta in the last ten years term, which has increased from 99, in 1985, till 189, in 1995, coincidentally with the massive country fumigations, with herbicides, as Paraquant or Glycofosfate. Other factors such an insufficient nourishment with hypovitaminosis B, alcoholism, tobacco addiction, etc., working isolate or jointly, are contemplated. Also are taken into account links between these factors and the corresponding pathologies. The AA. set out the biochemical process from which B vitamin deficiency with energetic ATP depletion trigger a cascade of reactions with release of free radicals and PAF, among other responses. Weedkillers block vitamin B coenzymes in Krebs cycle. Free radicals brake the H links of DNA chromosomes of both spermatozoon and ovule, carrying genetic malformations in descendents. And the same if acting metabollically in embrionary state because the reduction of acetylcoline synthese and consequently failure of vascular system and tissue development. Or directly inflammatory in the cell for virus, alcohol, etc.

Abnormalities, Drug-Induced↗
PubMed2002

[Effects of sulphur dioxide on the relationship between symbionts in lichen].

Xanthoparmellia mexicana was successfully isolating and culturing from its two symbionts and, preliminarily re-symbiosising its thalli in vitro performed from pure cultured photobiont and mycobiont. The solution exposure method was applied, confirming the toxic effect of sulfite solution with pH 4.0. The biochemical responses of lichen thalli and cultured symbionts to the short time stress of SO2 were studied. The chlorophyll PQa value of photobiont was correlated with its absorption of SO2. Chlorophyll a was more sensitive than chlorophyll b; chlorophyll was damaged most severely by the exposure of 0.5 mg.L-1 of SO2 fumigation, but was aggravated with the increase in the concentration of SO2 by way of solution exposure. The activity of acid phosphatase in lichen was mainly dependent on the photobiont. Reduced glutathione(GSH) was activated by oxidative stress of SO2. GSH was confirmed to be highly correlated with SO2 stress, and was proposed to be a significant and prospective biomarker of the status of lichen antioxidant system and the oxidative damage in lichen. The mycobiont was proposed to mainly resist the oxidative stress by SO2, while the photobiont was damaged more easily with energy depletion.

Ascomycota↗
PubMed2002

[Potential of purifying SO2 of main tree species and their planting quota in Shenyang area].

The total potential of purifying SO2 of main tree species was studied by using the combination of field measurement and fumigation experiment in this paper. The integrated value of purifying SO2 including total bimass, absorption intensity of SO2, and absorption-transformation periods of sulfur by trees was 4.39 x 10(6) kg, which was accounted for 3.66% of total sulfur released per year in Shenyang. It indicated that the maximum daily potential of purifying SO2 of trees might be 12.19 kg.km-2. Supposed that the average annual absorption capacity for sulfur of trees in Shenyang was 0.70 kg per tree and the average annual absorption capacity for sulfur of broad-leaved trees was 1.35 kg.tree-1, 88.88 million broad-leaved trees would be required to purify the annual released SO2 thoroughly. This number was equivalent to 12.9 times of existing trees. On the conditions of strengthening environmental protection and decreasing 20% of annual released sulfur, if the broad-leaved trees was double of the present number, SO2 content in air might be below 0.06 mg.m-3 and Shenyang would become a standardizing city with clear air.

Air Pollution↗
PubMed2002

[Guidelines for disinfection and sterilization].

I described the contents of the 'Guidelines for Disinfection and Sterilization' published based on the new infection law that came into effect in April 1999. This guideline does not recommend formaldehyde fumigation, disinfectant fogging, or the use of cresol soaps, but recommends disinfection methods with heat(hot water, steam).

Cross Infection↗
PubMed2002

Household papular urticaria.

BACKGROUND: Papular urticaria often occurs after bites of insects such as mosquitoes, sandflies, bed bugs and fleas. Multiple bites and local pruritus are characteristic symptoms. Treatment is usually symptomatic and includes antihistamines and corticosteroids. The reappearance of the symptoms can be prevented by successful control of the parasite. OBJECTIVES: To find the causative agent of papular urticaria in afflicted households with involvement of numerous family members, all in a narrow geographic area. PATIENTS: We describe the cases of 20 patients belonging to seven families, who presented to the local primary clinic, suffering from papular urticaria. RESULTS: The cat flea, Ctenocephalides felis, was the hematophagous insect responsible for all infestations. The pruritus and the papular urticaria were treated symptomatically with calamine lotion, topical corticosteroids or oral antihistamines. All clinical symptoms disappeared within a few weeks after effective control of the parasites by spraying and fumigating the infested locations. CONCLUSIONS: Thorough investigation--including, at times, environmental inspection--is necessary to reach the rewarding discovery of the etiology of household papular urticaria. This condition may arise in other environments of similar character.

Adult↗
PubMed1998

NTP Toxicology and Carcinogenesis Studies of 1-Chloro-2-propanol (Technical Grade) (CAS NO. 127-00-4) in F344/N Rats and B6C3F1 Mice (Drinking Water Studies.

1-Chloro-2-propanol and its positional isomer, 2-chloro-1-propanol, are used as chemical intermediates for the manufacture of propylene oxide, a starting material for production of polyurethane polyols and propylene glycol. The National Cancer Institute nominated 1-chloro-2-propanol for study because of potential for human exposure due to its residues in various foods that are fumigated with ethylene oxide or propylene oxide. Male and female F344/N rats and B6C3F1 mice were exposed to technical grade 1-chloro-2-propanol (75% to 76%% 1-chloro-2-propanol; 24% to 25%% 2-chloro-1-propanol) in drinking water for 14 days, 14 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, Drosophila melanogaster, and mouse peripheral blood erythrocytes. Continuous breeding studies were conducted in Sprague-Dawley rats. 14-DAY STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were administered 1-chloro-2-propanol in drinking water at concentrations of 0, 100, 330, 1,000, 3,300, or 10,000 ppm for 14 days. Two 10,000 ppm females died before the end of the study. The final mean body weights and body weight gains of 3,300 and 10,000 ppm rats were significantly less than those of the controls; rats in the 10,000 ppm groups lost weight. Water consumption by the 3,300 and 10,000 ppm groups was significantly less than that by the controls throughout the study. The thymus weights of 10,000 ppm rats were significantly less than those of the controls. Exposure to 1-chloro-2-propanol caused cytoplasmic alteration and degeneration of the acinar cells and fatty change in the pancreas, atrophy of the bone marrow, and atrophy and hematopoiesis of the spleen in males and females. 14-DAY STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were administered 1-chloro-2-propanol in drinking water at concentrations of 0, 100, 330, 1,000, 3,300, or 10,000 ppm for 14 days. One male mouse in the 10,000 ppm group died before the end of the study. Mean body weight gains of 10,000 ppm mice were significantly less than those of the controls. Water consumption by 3,300 and 10,000 ppm males and females was significantly less than that by the controls throughout the study. Liver weights of 1,000, 3,300, or 10,000 ppm males and females were significantly greater and thymus weights of 10,000 ppm mice were significantly less than those of the controls. Exposure to 1-chloro-2-propanol caused hepatocellular vacuolization, cytoplasmic alteration and degeneration of the pancreas acinar cells, and atrophy of the spleen in males and females. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were administered 1-chloro-2-propanol at concentrations of 0, 33, 100, 330, 1,000, or 3,300 ppm (equivalent to average daily doses of approximately 5, 10, 35, 100, or 220 mg/kg) for 14 weeks. All rats survived to the end of the study. Mean body weight gains of 3,300 ppm rats were significantly less than those of the controls. Water consumption by the 3,300 ppm male and female rats was significantly less than that by the controls. A minimal to mild anemia was observed in exposed female rats. The cauda epididymis and epididymis weights of 3,300 ppm males were significantly less than those of the controls. The percentage of abnormal sperm in 3,300 ppm males and the concentration of epididymal sperm in 330 ppm males were significantly increased compared to the controls. Kidney and liver weights of males and females exposed to 100 ppm or more were generally greater than those of the controls. The incidences of acinar cell degeneration and fatty change of the pancreas in 1,000 and 3,300 ppm rats, hepatocytic metaplasia of the pancreatic islets in 3,300 ppm females, cytoplasmic vacuolization of the liver in 100, 1,000 and 3,300 ppm males, and renal tubule epithelium regeneration in 3,300 ppm females were increased compared to the controls. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were administered 1-chloro-2-propanol in drinking water at concentrations of 0, 33, 100, 33entrations of 0, 33, 100, 330, 1,000, or 3,300 ppm (equivalent to average daily doses of approximately 5, 15, 50, 170, or 340 mg/kg to males and 7, 20, 70, 260, or 420 mg/kg to females) for 14 weeks. One 330 ppm male died before the end of the study. Mean body weight gains of exposed groups were similar to those of the controls. A minimal anemia was observed in 3,300 ppm males. The right epididymis weight of 3,300 ppm males was significantly greater than that of the controls. Kidney weights of 3,300 ppm mice, liver weights of 1,000 ppm males and of all exposed groups of females, and thymus weights of 1,000 and 3,300 ppm females were greater than those of the controls. The incidences of pancreatic acinar cell degeneration and fatty change in 3,300 ppm males and females and cytoplasmic vacuolization of the liver in all groups of exposed females were significantly increased compared to the controls. The severities of renal tubule cytoplasmic vacuolization were greater in 1,000 and 3,300 ppm males than in the controls. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female F344/N rats were administered drinking water containing 0, 150, 325, or 650 ppm 1-chloro-2-propanol (equivalent to average daily doses of approximately 15, 30, or 65 mg/kg during the first several months of the study and 8, 17, or 34 mg/kg for the remainder of the 2-year study) for up to 105 weeks. Survival of all exposed groups was similar to that of the controls. Mean body weights of exposed rats were generally similar to those of the controls throughout most of the study. Water consumption by all exposed groups was similar to that by the controls. No treatment-related neoplasms or nonneoplastic lesions were observed in this study. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female B6C3F1 mice were administered drinking water containing 0, 250, 500, or 1,000 ppm 1-chloro-2-propanol (equivalent to average daily doses of approximately 45, 75, or 150 mg/kg to males and 60, 105, or 210 mg/kg to females during the first several months of the study and 25, 50, or 100 mg/kg for the remainder of the 2-year study) for up to 105 weeks. Survival of all exposed groups was similar to that of the controls. The mean body weights of all exposed mice were generally similar to those of the controls throughout the study. Water consumption by all exposed groups was similar to that by the controls. No treatment- related neoplasms or nonneoplastic lesions were observed in this study. GENETIC TOXICOLOGY: 1-Chloro-2-propanol is a demonstrated mutagen in vitro. It was weakly mutagenic in S. typhimurium strain TA100 in the presence of hamster or rat liver S9 activation enzymes and was positive, with and without S9, in TA1535. No mutagenic activity was detected in strains TA97, TA98, and TA1537, with or without S9. In cytogenetic tests with Chinese hamster ovary cells, 1-chloro-2-propanol induced high levels of sister chromatid exchanges and chromosomal aberrations in the presence and the absence of S9. The marked ability of 1-chloro-2-propanol to induce chromosomal effects in vitro was not seen in vivo. Positive results were obtained in a test in D. melanogaster for induction of sex-linked recessive lethal mutations in germ cells of males administered 1-chloro-2-propanol via injection; however, negative results were obtained when males were administered 1-chloro-2-propanol in feed. A subsequent germ cell reciprocal translocation test in D. melanogaster yielded negative results. Further, no induction of micronucleated erythrocytes was observed in peripheral blood of male and female mice administered 1-chloro-2-propanol via drinking water for 14 weeks. CONCLUSIONS: Under the conditions of these 2-year drinking water studies, there was no evidence of carcinogenic activity of technical grade 1-chloro-2-propanol in male or female F344/N rats exposed to 150, 325, or 650 ppm. There was no evidence of carcinogenic activity of technical grade 1-chloro-2-propanol in male or female B6C3F1 mice exposed to 250, 500, or 1,000 ppm. Synonyms: 1-Chloro-2-hydroxypropane, 1-chloroisopropyl alcohol, propylene-α-chlorohydrin, sec-propylene chlorohydrin

Journal Article↗
PubMed1997

NTP Toxicology and Carcinogenesis Studies of Nitromethane (CAS No. 75-52-5) in F344/N Rats and B6C3F1 Mice (Inhalation Studies).

Nitromethane is used as a rocket and engine fuel; as a synthesis intermediate for agricultural fumigants, biocides, and other products; as a solvent; and as an explosive in mining, oil-well drilling, and seismic exploration. It has been detected in air, in surface and drinking water, and in cigarette smoke. Nitromethane was studied because of the potential for widespread human exposure and because it is structurally related to the carcinogens 2-nitropropane and tetranitromethane. Male and female F344/N rats and B6C3F1 mice received nitromethane (purity 98% or greater) by inhalation for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and peripheral blood erythrocytes of mice. 16-DAY STUDY IN RATS: Groups of five male and five female rats were exposed to 0, 94, 188, 375, 750, or 1,500 ppm nitromethane by inhalation, 6 hours per day, 5 days per week, for 16 days. All rats survived until the end of the study. The mean body weight gain of male rats in the 1,500 ppm group was slightly but significantly less than that of the controls; the final mean body weights and mean body weight gains of exposed females were similar to those of the controls. Clinical findings in all male and female rats in the 1,500 ppm groups included increased preening, rapid breathing, hyperactivity early in the study, and hypoactivity and loss of coordination in the hindlimbs near the end of the study. The relative liver weights of all exposed groups of male rats and the absolute and relative liver weights of females exposed to 375 ppm or greater were significantly greater than those of the controls. Minimal to mild degeneration of the olfactory epithelium was observed in the nose of males and females exposed to 375 ppm or greater. Sciatic nerve degeneration was present in all male and female rats exposed to 375 ppm or greater; rats exposed to 750 or 1,500 ppm also had reduced myelin around sciatic axons. 16-DAY STUDY IN MICE: Groups of five male and five female mice were exposed to 0, 94, 188, 375, 750, or 1,500 ppm nitromethane by inhalation, 6 hours per day, 5 days per week, for 16 days. All mice survived to the end of the study. The final mean body weights and weight gains of exposed males and females were similar to those of the controls. Clinical findings included hypoactivity and tachypnea in male and female mice in the 1,500 ppm groups. Absolute and relative liver weights of male mice in the 750 and 1,500 ppm groups and female mice in all exposed groups and the relative liver weight of males in the 375 ppm group were significantly greater than those of the controls. Degeneration of the olfactory epithelium of the nose was observed microscopically in all males and females exposed to 375 ppm or greater; this lesion was of minimal severity in males and minimal to mild severity in females. 13-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were exposed to 0, 94, 188, 375, 750, or 1,500 ppm nitromethane by inhalation, 6 hours per day, 5 days per week, for 13 weeks. All rats survived to the end of the study. The final mean body weight and weight gain of male rats in the 1,500 ppm group were significantly less than those of the controls. Clinical findings included hindlimb paralysis in rats in the 750 and 1,500 ppm groups. Inhalation exposure of rats to nitromethane resulted in an exposure concentration-dependent, microcytic, responsive anemia; anemia was most pronounced in males and females exposed to 375 ppm or greater. The presence of schistocytes, Heinz bodies, and spherocytes and increased mean cell hemoglobin concentration and methemoglobin concentration were evidence that a hemolytic process was occurring; this hemolytic process could have accounted, in part, for the anemia. Thrombocytosis accompanied the anemia and would be consistent with a reactive bone marrow or could have been due to the erroneous inclusion of small erythrocyte fragments as part of the platelet count. On day 23, transient decreases in serum triiodothyronine, thyroxine, and fr and free thyroxine were observed in male rats exposed to 375 ppm or greater and female rats exposed to 750 or 1,500 ppm. There was little or no pituitary response to the thyroid hormone decreases, as evidenced by the lack of significantly increased concentrations of thyroid-stimulating hormone in exposed rats. No biologically significant differences in organ weights were observed. The forelimb and hindlimb grip strengths of males in the 1,500 ppm group were significantly less than those of the controls. The hindlimb grip strengths of females in the 750 and 1,500 ppm groups were also significantly less than the control value. Minimal to mild hyperplasia of the bone marrow was observed microscopically in male rats in the 750 and 1,500 ppm groups and in females exposed to 188 ppm or greater. Nasal lesions in exposed males and females included olfactory epithelial degeneration in males and females exposed to 375 ppm or greater and in one female exposed to 188 ppm and respiratory epithelial hyaline droplets and goblet cell hyperplasia in males and females in the 750 and 1,500 ppm groups; the severity of nasal lesions in males and females was minimal to mild. Males and females exposed to 375 ppm or greater had minimal to mild degeneration of the sciatic nerve and the lumbar spinal cord. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were exposed to 0, 94, 188, 375, 750, or 1,500 ppm nitromethane by inhalation, 6 hours per day, 5 days per week, for 13 weeks. All mice survived to the end of the study. The final mean body weights and weight gains of exposed mice were generally similar to those of the controls. There were no treatment-related clinical findings. The absolute right kidney weights of all groups of exposed male mice except the 1,500 ppm group and of females exposed to 188 ppm or greater and the relative right kidney weights of all groups of exposed males and of females in the 750 and 1,500 ppm groups were significantly greater than those of the controls. The absolute liver weight of male mice in the 750 ppm group and the relative liver weights of males exposed to 375 ppm or greater were significantly greater than those of the controls. Olfactory epithelial degeneration and respiratory epithelial hyaline droplets were observed microscopically in all male and female mice exposed to 375 ppm or greater. Degeneration also occurred in females in the 188 ppm group, and hyaline droplets occurred in females in the 94 and 188 ppm groups. The average severity of the nasal lesions ranged from minimal to mild in males. In females, the average severity of olfactory epithelial degeneration ranged from minimal to mild and the severity of respiratory epithelial hyaline droplets ranged from minimal to moderate. All males and nine females in the 1,500 ppm groups also had minimal extramedullary hematopoiesis of the spleen. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats were exposed to 0, 94, 188, or 375 ppm nitromethane by inhalation, 6 hours per day, 5 days per week, for 103 weeks. Survival,Body Weights, and Clinical Findings: There were no significant differences in survival rates between exposed and control male or female rats. The mean body weight of females in the 375 ppm group was slightly greater than that of the control group; the mean body weights of exposed males were generally similar to the mean body weight of the controls throughout the study. Clinical findings were consistent with incidences of mammary gland neoplasms in females exposed to 188 or 375 ppm; no hindlimb paralysis, as occurred in rats in the 13-week study, was observed in male or female rats in the 2-year study. Pathology Findings: The incidences of mammary gland fibroadenoma and fibroadenoma, adenoma, or carcinoma (combined) in female rats in the 188 and 375 ppm groups were significantly greater than those in the controls. Additionally, the incidences of mammary gland carcinoma in the 375 ppm group were significantly greater than those in the controls. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice were exposed to 0, 188, 375, or 750 ppm nitromethane by inhalation, 6 hours per day, 5 days per week, for 103 weeks. Survival,Body Weights, and ClinicalFindings The survival rate of females in the 750 ppm group was marginally greater than that of the controls. The mean body weights of exposed females were generally slightly greater than the mean body weights of the controls during the study but were generally similar to the mean body weight of the controls at the end of the study. The mean body weights of exposed males were similar to those of the controls throughout the study. Clinical findings included swelling around the eyes and exophthalmos in exposed males and females; these findings were coincident with harderian gland neoplasms. Pathology Findings: The incidences of harderian gland adenoma and adenoma or carcinoma (combined) in exposed mice increased with increasing exposure concentration and were significantly greater in males and females in the 375 and 750 ppm groups than those in the controls. The incidences of harderian gland carcinoma in males and females in the 375 and 750 ppm groups were also slightly greater than those in the controls. Female mice in the 188 and 750 ppm groups had significantly greater incidences of hepatocellular adenoma and hepatocellular adenoma or carcinoma (combined) than the controls. The incidences of liver eosinophilic focus increased with increasing exposure concentration, and the incidences in the 375 and 750 ppm groups were significantly greater than the control incidence. The incidences of alveolar/bronchiolar carcinoma in male mice in the 750 ppm group and female mice in the 375 ppm group were significantly greater than those in the controls. Females in the 750 ppm group also had a significantly greater incidence of alveolar/bronchiolar adenoma or carcinoma (combined) and a slightly greater incidence of alveolar/bronchiolar adenoma than the controls. Females in the 375 ppm group had a significantly greater incidence of cellular infiltration of histiocytes in the lung than the controls. The incidences of degeneration and metaplasia of the olfactory epithelium and hyaline degeneration of the respiratory epithelium were significantly greater in exposed male and female mice than those in the controls. Additionally, males in the 375 and 750 ppm groups had significantly greater incidences of inflammation of the nasolacrimal duct than did the controls. GENETIC TOXICOLOGY: Nitromethane was not mutagenic in any tests performed by the NTP. It did not induce mutations in Salmonella typhimurium, with or without S9 metabolic activation, and no induction of sister chromatid exchanges or chromosomal aberrations in cultured Chinese hamster ovary cells exposed to nitromethane was noted with or without S9. No increase in the frequency of micronucleated erythrocytes was observed in peripheral blood samples of male and female mice at the end of the 13-week inhalation study of nitromethane. CONCLUSIONS: Under the conditions of these 2-year inhalation studies, there was no evidence of carcinogenic activity of nitromethane in male F344/N rats exposed to 94, 188, or 375 ppm. There was clear evidence of carcinogenic activity of nitromethane in female F344/N rats based on increased incidences of mammary gland fibroadenomas and carcinomas. There was clear evidence of carcinogenic activity of nitromethane in male B6C3F1 mice based on increased incidences of harderian gland adenomas and carcinomas. There was clear evidence of carcin ogenic activity in female B6C3F1 mice, based on increased incidences of liver neoplasms (primarily adenomas) and harderian gland adenomas and carcinomas. Increased incidences of alveolar/bronchiolar adenomas and carcinomas in male and female mice exposed to nitromethane were also considered to be related to chemical administration. Exposure to nitromethane by inhalation for 2 years resulted in increased incidences of nasal lesions including degeneration and metaplasia of the olfactory epithelium and degeneration of the respiratory epithelium in male and female mice. Synonym: Nitrocarbol

Journal Article↗
PubMed1992

NTP Toxicology and Carcinogenesis Studies of Methyl Bromide (CAS: 74-83-9) in B6C3F1 Mice (Inhalation Studies).

Methyl bromide is widely used as a fumigant and pesticide. Toxicology and carcinogenesis studies were conducted by exposing groups of male and female B6C3F1 mice to methyl bromide (99.8% pure) by inhalation 6 hours per day, 5 days per week, for 14 days, 6 weeks, 13 weeks, or 2 years. Six-week and 13-week inhalation toxicity studies in F344/N rats were conducted concurrently with the mouse studies. Hematology parameters were measured during the 6-week, 13-week, and 2-year studies. Quantitative neurobehavioral testing was performed during the 14-day, 13-week and 2-year studies. Genetic toxicology studies were conducted for gene mutation induction in Salmonella typhimurium and for induction of sister chromatid exchanges in mouse bone marrow cells and of micronuclei from peripheral blood erythrocytes. 14-Day Studies: Groups of five B6C3F1 mice of each sex were exposed to 0, 12, 25, 50, 100, or 200 ppm methyl bromide by inhalation 6 hours per day, 5 days per week for 2 weeks. Only four female mice and one male mouse survived 10 exposures at 200 ppm. No deaths occurred at the lower doses. Neurobehavioral effects including trembling and paralysis were noted in all groups, but were most pronounced in the three highest dose groups. Red urine was noted in the mice exposed to 200 ppm. 13-Week Studies : Groups of 10 mice of each sex were exposed to 0, 10, 20, 40, 80, or 120 ppm methyl bromide by inhalation 6 hours per day, 5 days per week for 13 weeks. Additional groups of eight to 17 mice were concurrently exposed for neurobehavioral and genetic toxicology studies. The final mean body weight of males exposed to 120 ppm was significantly (12%) lower than that of the controls. Four of 24 males exposed to 120 ppm died during the study. Groups of 10 rats of each sex were exposed to 0, 30, 60, or 120 ppm methyl bromide by inhalation 6 hours per day, 5 days per week for 13 weeks. Additional groups of eight rats were concurrently exposed for neurobehavioral studies. Final mean body weights of rats exposed to 120 ppm were 12% lower than those of the controls for males and 13% lower for females. No rats died as a result of methyl bromide exposure during the studies. Special 6-Week Target Organ Toxicity Studies: Neither the 14-day nor the 13-week studies provided strong evidence for specific organ toxicity. Six-week studies were therefore conducted to identify target organs for the 2-year studies. Groups of 20 rats and mice of each sex were exposed to methyl bromide by inhalation for 6 hours per day, 5 days per week for 6 weeks at a dose of 160 ppm. Mortality rates exceeded 50% in the male mice after eight exposures, in female mice after six exposures, and in male rats after 14 exposures. Only the female rat group survived 30 exposures with less than 50% mortality. The study identified the brain, kidney, nasal cavity, heart, adrenal gland, liver, and testis as the primary organs to examine for toxicity in the 2-year methyl bromide inhalation studies. 2-Year Studies: Groups of 70 B6C3F1 mice of each sex were exposed to methyl bromide by inhalation at 0, 10, 33, or 100 ppm for 6 hours per day, 5 days per week for up to 103 weeks. Additional groups of 16 mice were included for neurobehavioral evaluations throughout the 2-year studies. By 20 weeks (139 days), 27 males and 7 females exposed to 100 ppm had died and methyl bromide exposure was discontinued for the remaining mice in this dose group. Ten female mice from the 100 ppm group predesignated for the 15-month interim evaluation were killed on schedule and all other high-dose animals were allowed to live to term (24 months) for evaluation of chronic toxicity and carcinogenicity. Clinical signs indicative of neurotoxicity, including tremors, abnormal posture, tachypnea, and hind leg paralysis, persisted in these high-dose mice until the end of the studies. Final mean body weights of surviving 100 ppm males and females were markedly lower (33% and 31%) than those of the controls. Neurobehavioral changes occurred in male and female mice initially exposed to 100 ppm methyl bromide, with more prnitially exposed to 100 ppm methyl bromide, with more pronounced changes observed in males. In general, these animals were less active and manifested a heightened sensitivity in the startle response than mice in other dose groups. Exposure to methyl bromide was not carcinogenic under the conditions of these studies. However, there was an increase in the incidence of several nonneoplastic lesions in the brain, heart, bone (sternum), and nose. Degenerative changes in the cerebellum and cerebrum occurred in males and females exposed to 100 ppm. Myocardial degeneration and cardiomyopathy were observed in the hearts of mice exposed to 100 ppm. An increased incidence of sternal dysplasia was seen in treated animals, particularly in those exposed to 100 ppm. An increased incidence of olfactory epithelial necrosis and metaplasia within the nasal cavity was seen in the mice exposed to 100 ppm, particularly males. Genetic Toxicology: Methyl bromide was positive for induction of gene mutations in Salmonella typhimuriumstrain TA100, with and without exogenous metabolic activation; negative results were obtained with TA98 in this assay. In vivo, methyl bromide induced sister chromatid exchanges in bone marrow cells and micronuclei in peripheral erythrocytes of female mice exposed by inhalation for 14 days. No significant increase in either sister chromatid exchanges or micronuclei was observed in male or female mice exposed to methyl bromide by inhalation for 4, 8, or 12 weeks. Conclusions: Under the conditions of these 2-year inhalation studies, methyl bromide caused degenerative changes in the cerebellum and cerebrum, myocardial degeneration and cardiomyopathy, sternal dysplasia, and olfactory epithelial necrosis and metaplasia. Toxic effects persisted although exposure to methyl bromide in the 100 ppm group terminated after 20 weeks. There was no evidence of carcinogenic activity of methyl bromide in male or female B6C3F1 mice exposed to 10, 33, or 100 ppm. Synonym: Bromomethane

Journal Article↗
PubMed1993

NTP Toxicology and Carcinogenesis of 1,2,3-Trichloropropane (CAS No. 96-18-4) in F344/N Rats and B6C3F1 Mice (Gavage Studies).

1,2,3-Trichloropropane is a colorless liquid used as a paint and varnish remover, solvent, and degreasing agent, and as a crosslinking agent in the synthesis of polysulfides and hexafluoropropylene. 1,2,3-Trichloropropane may be found as an impurity in certain nematocides and soil fumigants and as a contaminant of drinking and ground water. Studies on the toxic and carcinogenic effects of 1,2,3-trichloropropane were initiated because of the close structural relationship of this chemical to other short-chain halogenated compounds that were demonstrated to be carcinogenic in experimental animals, and because of the potential for human exposure. Toxicology and carcinogenicity studies were conducted by administering 1,2,3-trichloropropane (greater than 99% pure) in corn oil by gavage to groups of F344/N rats and B6C3FI mice for 17 weeks and 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium strains, mouse lymphoma cells, and Chinese hamster ovary cells. 17-Week Studies: Groups of 20 male and 20 female rats received 1,2,3-trichloropropane in corn oil by gavage at doses of 8, 16, 32, 63, 125, or 250 mg/kg body weight 5 days per week for up to 17 weeks; 30 male and 30 female rats received corn oil alone and served as controls. Animals were evaluated at 8 or 17 weeks. All rats in the 250 mg/kg groups died by week 5. One male and four female rats in the 125 mg/kg groups died during the study. The mean body weight gains and final mean body weights of males receiving 63 mg/kg and of males and females receiving 125 mg/kg were lower than those of the controls. Hematocrit values, hemoglobin concentrations, and erythrocyte counts decreased with dose in males and females. Serum alanine aminotransferase, aspartate aminotransferase, and sorbitol dehydrogenase activities were significantly increased in some female rats receiving 125 mg/kg. Serum pseudocholinesterase activity decreased with dose in females. Increases in kidney and liver weights were related to chemical administration. The principal toxic lesions associated with the administration of 1,2,3-trichloropropane to rats were hepatocellular necrosis, karyomegaly, and biliary hyperplasia of the liver; renal tubule necrosis, regeneration, and karyomegaly of the kidney; and necrosis and inflammation of the nasal olfactory and respiratory epithelium. Groups of 20 male and 20 female mice received 1,2,3-trichloropropane in corn oil by gavage at doses of 8, 16, 32, 63, 125, or 250 mg/kg 5 days per week for up to 17 weeks; 30 male and 30 female mice received corn oil alone and served as controls. Sixteen male and seven female mice in the 250 mg/kg groups died by week 4. The final mean body weights and mean body weight gains of dosed mice were similar to those of the controls, except those of 250 mg/kg males, which were lower than those of controls. The principal toxic lesions associated with the administration of 1,2,3-trichloropropane were hepatocellular necrosis and karyomegaly of the liver; necrosis, regeneration, and hyperplasia of the bronchiolar epithelium in the lung; and acanthosis (hyperplasia) and hyperkeratosis of the forestomach epithelium. 2-Year Studies: Groups of 60 male and 60 female rats received 0, 3, 10, or 30 mg 1,2,3-trichloropropane/kg body weight in corn oil by gavage 5 days per week for up to 104 weeks. Selection of 30 mg/kg as the high dose in these studies was based on the following chemical-related effects in the 17-week studies: deaths and liver and kidney lesions at 125 and 250 mg/kg and reduced final mean body weights and mean body weight gains at 63 mg/kg or greater. Groups of 60 male and 60 female mice received 0, 6, 20, or 60 mg 1,2,3-trichloropropane/kg body weight in corn oil by gavage 5 days per week for up to 104 weeks. Selection of 60 mg/kg as the high dose was based on chemical-related deaths and lesions of the liver, lung, and forestomach at 125 and 250 mg/kg in the 17-week studies. 15-Month Interim Evaluations: Up to 10 rats and 10 mice from each dose group were evaluated at 15 months. Absolute and relative liver and kidned kidney weights of dosed rats were significantly greater than those of the controls. Chemical-related nonneoplastic lesions and neoplasms of the forestomach, oral mucosa, pancreas (males), kidney, mammary gland (females), preputial gland, and clitoral gland were observed in dosed rats. Chemical-related nonneoplastic lesions and neoplasms of the forestomach and liver (females) were observed in dosed mice. Survival and Body Weight in the 2-Year Studies: Survival of male and female rats receiving 10 or 30 mg/kg 1,2,3-trichloropropane was significantly lower than that of controls. Two-year survival rates of male rats were: control, 34/50; 3 mg/kg, 32/50; 10 mg/kg, 14/49; 30 mg/kg, 0/52; and of females were: 31/50, 30/49, 8/52, 0/52. At 30 mg/kg, survival was markedly reduced due to chemical-related neoplasms, and survivors were killed in weeks 67 (females) or 77 (males). Final mean body weights of 30 mg/kg rats were 13% lower for males and 12% lower for females than those of controls; mean body weights of 3 and 10 mg/kg rats were similar to controls. Survival rates of mice receiving 6, 20, or 60 mg/kg 1,2,3-trichloropropane were also significantly lower than those of controls. Two-year survival rates of male mice were: 42/52, 18/51, 0/54, 0/56; and of female mice were: 41/50, 13/50, 0/51, 0/55. Because of reduced survival at 20 and 60 mg/kg due to chemical-related neoplasms, survivors were killed in weeks 73 (60 mg/kg females), 79 (60 mg/kg males), or 89 (20 mg/kg males and females). Final mean body weights were 16% lower for 60 mg/kg males, 18~ lower for 60 mg/kg females, and 13% lower for 20 mg/kg males than those of controls. Final mean body weights of 6 mg/kg males and females and 20 mg/kg females were similar to controls. Neoplasms and Nonneoplastic Lesions in the 2-Year Studies: Administration of 1,2,3-trichloropropane to rats induced benign and malignant neoplasms of the oral mucosa (pharynx and tongue), forestomach, and preputial and clitoral glands in males and females; benign neoplasms of the exocrine pancreas and kidney in males, and malignant neoplasms of the mammary gland in females. The incidences of squamous cell papillomas and carcinomas of the oral mucosa were significantly increased in 10 and 30 mg/kg rats, while the incidences of squamous cell papillomas or carcinomas (combined) of the forestomach were significantly increased in all dosed groups. The incidence of pancreatic acinar adenoma was significantly increased in dosed males, but not in dosed females. Similarly, the incidence of adenoma of the kidney was significantly increased in 10 and 30 mg/kg male rats only. The incidences of adenoma or carcinoma (combined) of the preputial gland in 30 mg/kg males and of the clitoral gland in 10 and 30 mg/kg females (homologous organs) were significantly increased. The incidence of adenocarcinoma of the mammary gland was significantly increased in the 10 and 30 mg/kg females. The incidences of Zymbal's gland carcinomas were increased in 30 mg/kg males and females. Adenocarcinomas of the intestine occurred in small numbers of dosed rats and may have been chemical related. In mice, the incidence of squamous cell carcinoma of the oral mucosa was significantly increased only in 60 mg/kg females. In contrast, the incidences of squamous cell papilloma and carcinoma of the forestomach were significantly increased in all groups of dosed mice. The incidences of hepatocellular adenoma or carcinoma (combined) were significantly increased in all dosed groups of males and 60 mg/kg females. The incidences of harderian gland adenoma were significantly increased in 20 mg/kg males and in 60 mg/kg males and females. The incidences of uterine adenoma, adenocarcinoma, and stromal polyp were significantly increased in 60 mg/kg females. Genetic Toxicology: 1,2,3-Trichloropropane was mutagenic in vitro in the presence of S9 metabolic activation. At two laboratories, positive responses were obtained for mutagenicity in Salmonella typhimurium strains TA97, TA98, TA100, and TA1535 in the presence of S9; no mutagenic activity was observed in TA1537, with or without S9. 1,2,3-Trichloropropane induced trifluorothymidine resistance in L5178Y mouse lymphoma cells with, but not without, S9. In cultured Chinese hamster ovary cells, sister chromatid exchanges and chromosomal aberrations were induced by 1,2,3-trichloropropane; however, significant increases in the endpoints of both cytogenetic effects occurred only in the presence of S9. Conclusions: Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenic activity of 1,2,3-trichloropropane in male F344/N rats based on increased incidences of squamous cell papillomas and carcinomas of the oral mucosa and forestomach, adenomas of the pancreas and kidney, adenomas or carcinomas of the preputial gland, and carcinomas of the Zymbal's gland. Adenomatous polyps and adenocarcinomas of the intestine may have been related to chemical administration. There was clear evidence of carcinogenic activity of 1,2,3-trichloropropane in female F344/N rats based on increased incidences of squamous cell papillomas and carcinomas of the oral mucosa and forestomach, adenomas or carcinomas of the clitoral gland, adenocarcinomas of the mammary gland, and carcinomas of the Zymbal's gland. Adenocarcinomas of the intestine may have been related to chemical administration. There was clear evidence of carcinogenic activity of 1,2,3-trichloropropane in male B6C3F1 mice based on increased incidences of squamous cell papillomas and carcinomas of the forestomach, hepatocellular adenomas or carcinomas of the liver, and harderian gland adenomas. Squamous cell papillomas of the oral mucosa may have been related to chemical administration. There was clear evidence of carcinogenic activity of 1,2,3-trichloropropane in female B6C3F1, mice based on increased incidences of squamous cell carcinomas of the oral mucosa, squamous cell papillomas and carcinomas of the forestomach, hepatocellular adenomas or carcinomas of the liver, harderian gland adenomas, and uterine adenomas, adenocarcinomas, and stromal polyps. Nonneoplastic lesions associated with exposure to 1,2,3-trichloropropane included increased severity of nephropathy in male rats and increased incidences of basal cell and squamous hyperplasia of the forestomach, acinar hyperplasia of the pancreas, renal tubule hyperplasia, and preputial or clitoral gland hyperplasia in male and female rats. Increased incidences of squamous hyperplasia of the forestomach and eosinophilic foci in the liver in male and female mice were chemical related. Synonyms: Allyl trichloride, glycerol tnchlorohydrin, glyceryl tnchlorohydrin, trichlorohydrin

Journal Article↗
PubMed2003

[Chemical components of volatile oil from Mikania micrantha and its biological activity on insects].

The chemical components of volatile oil from Mikania micrantha were analyzed by GC/MS. Twenty-two compounds were identified, and monoterpenes and sesquiterpenes as well as alcohol and ketone with their derivatives were major components. Biological activity of volatile oil on insect was investigated. The results showed that the volatile oil had significant deterrent effect on oviposition of Plutella xylostella, Phyllotreta striolata and Phaedon brassicae at dose of 5-10 microliters.plant-1. They also possessed established contracting toxicity, and their rectifying reduce rates for Lipaphis erysimi were 50.0%, 59.86%, 62.51% at concentration of 500, 750, and 1000 mg.L-1, respectively. However, they had not fumigating toxicity for virginogeniae, L. erysimi, 2nd instar larvae of P. xylostella, and adult of P. striolata at concentration of 500 mg.L-1.

Animals↗
PubMedDate not supplied

[Reactive oxygen forms and luminescence of intact microspore cells].

The participation of reactive oxygen species (ROS) in luminescence (chemiluminescence and autofluorescence induced by ultraviolet light of 360-380 nm) was analyzed. Microspores, the pollen (male gametophyte) of Hippeastrum hybridum, Philadelphus grandiflorus, and Betula verrucosa and vegetative microspores of the spore-breeding plant Equisetum arvense served as models. It was found that the addition of the chemiluminescent probe lucigenin, which luminesces in the presence of superoxide anionradicals, leads to intensive chemiluminescence of microspores. No emission was observed in the absence of lucigenin and in the presence of the dye luminol as a chemiluminescent probe. The emission decreased significantly if superoxide dismutase, an enzyme of the superoxide anionradical dismutation during which this radical disappeared, was added before the dye addition. The autofluorescence intensity of microspores decreased in the presence of both superoxide dismutase and peroxidase, an enzyme destroying hydrogen peroxide and organic peroxides. The most significant effect was noted after the addition of peroxidase, which indicates a greater contribution of peroxides to this type of emission. The fumigation with ozone, which increases the amount of ROS on the cell surface, enhanced the intensity of the chemiluminescence of microspores with lucigenin, but decreased the intensity of the autofluorescence of microspores. Exogenous peroxides (hydrogen peroxide and tert-butylhydroperoxide) stimulated the autofluorescence of pollen and vegetative spores in a concentration-dependent manner. It was shown that the formation of ROS contributes to the luminescence of plant microspores, which reflects their functional state.

Betula↗
PubMed2003

[Sperm characteristics in fertile men and healthy men of the south-east Sicily from year 1982 to 1999].

OBJECTIVE: To investigate whether sperm density (D) and morphology (M) deteriorated in the last 18 years (from 1982 to 1999) in a South-East area of Sicily (Catania, Siracusa and Ragusa provinces). The area of residence of this subjects studied is a strong consumer in fumigants and pesticides in the hot-house factories and thus the present study can be useful to examine a possible negative impact of these compounds on sperm parameters through a long-term monitoring of an apparently healthy population. MATERIALS AND METHODS: Sperm D and M were retrospectively analysed in 716 men (median age 29, range 22-43 years) referring to the Andrology Center of the University of Catania. The subjects were subdivided in 2 groups: the first included subjects who fathered occasionally (n = 467), the second was formed by healthy volunteers consulting as possible donors (n = 109) and to check their fertility (n = 140). RESULTS: During the study period of 18 years, both sperm D and M (in terms of percentage of normal forms) showed significant (p < 0.01) time-dependent indirect correlations (r = -0.12 for D and r = -0.29 for NF). D exhibited two significant peak values in the years 1982, 1983 and 1994 respectively, followed by two periods (years 1984-1986, and 1995-1996) with not significantly declined values and then with values significantly lower than the above peak values in the years 1987, 1989, 1992 as well as in the period 1997-1999. The M registered a progressive decline, statistically significant in the years 1988 and 1994 in comparison to the preceding years. A further significant decrease in sperm M was registered, in comparison to the periods 1982-1987 and 1988-1994, in the period 1995-1999. CONCLUSION: Our data showed a temporal decline of sperm parameters in South-East area of the Sicilia, from 1982 to 1999, in fertile men and occasional healthy subjects or donors. These data confirmed the sperm deterioration registered in Europe. The results might be influenced by time-varying body of users of referring Andrology Center (i.e. oligozoospermic subjects preferring ART program have approached again our Center in the last years from the activation of our Unit of ART), and/or by varying temporal changes in the levels of environmental/occupational gonadotoxic factors.

Adult↗
PubMed1986

NTP Toxicology and Carcinogenesis Studies of 1,2-Dichloropropane (Propylene Dichloride) (CAS No. 78-87-5) in F344/N Rats and B6C3F1 Mice (Gavage Studies).

1,2-Dichloropropane is a chemical intermediate widely used in the production of tetrachloroethylene and carbon tetrachloride. It is an oil and fat solvent in certain furniture finishes, dry cleaning fluids, and paint removers and has been used to fumigate grain and soil and to control peach tree borers. Approximately 77 million pounds of 1,2-dichloropropane were produced in the United States in 1980. The current 8-hour time-weighted-average concentration to which workers may be exposed to is 75 ppm. Carcinogenesis studies of 1,2-dichloropropane (<99% pure) were conducted by administering the chemical in corn oil by gavage to groups of 50 female F344/N rats and 50 male and 50 female B6C3F1 mice at doses of 125 or 250 mg/kg body weight and to groups of 50 male F344/N rats at doses of 62 or 125 mg/kg body weight. Doses were administered five times per week for 103 weeks. Vehicle control groups of 50 rats and 50 mice of each sex received an equivalent amount of corn oil by gavage on the same dosing schedule. Survival was reduced for high dose female rats (P<0.001) and for high dose female mice (P<0.05) relative to controls; 16/50 high dose female rats and 26/50 high dose female mice survived to the end of the experiment. Survival in the other groups was comparable to the control groups. In female mice, ovarian, uterine, or multiple organ infections may have contributed to the deaths of 5/11 vehicle control, 9/14 low dose, and 14/22 high dose animals that died before the end of the study. There was no evidence of an adverse effect on survival in male rats or in male mice. Mean body weights of high dose male (-14%) and high dose female (-24%) rats were lower than those of the controls. Low dose rats and all groups of mice had mean body weights comparable to the controls. High dose female rats had increased incidences of both clear-cell changes and necrosis of the liver; but there was no increase in the incidence of liver tumors in the female rats. There was no treatment-related effects observed in the male rats, other than decreased body weights. Dose-related increases were observed for adenomas of the liver in both male (control, 7/50; low dose, 10/50; high dose 17/50) and female (1/50, 5/50, 5/50) mice. The increase in the frequency of liver carcinomas supported the evidence that there was a neoplastic response in the mouse liver for both sexes (males: 11/50, 17/50, 16/50, females: 1/50, 3/50, 4/50). Hepatocytomegaly and hepatic necrosis were increased in male mice, but not in female mice. A dose related increase in adenocarcinomas of the mammary gland was observed in female rats (control, 1/50; low dose, 2/50; high dose, 5/50) with the majority of these tumors being found at the end of the study (1/37, 3%; 2/43, 5%; 4/16, 25%). The incidence of mammary adenocarcinomas was increased when compared to the historical controls for this laboratory (3/150, 2.0%) and for all laboratories combined (11/895, 1.2%). Mammary fibroadenomas were decreased in the high dose treated female rats (15/50, 20/50, 7/50). The mutagenic activity of 1,2-dichloropropane was marginal. The compound was tested in strains TA100, TA98, TA1537, and TA1535 of Salmonella typhimurium in the presence or absence of S9 and no clearly positive response was obtained. Chromosomal aberration and sister chromatid exchange data showed that 1,2-dichloropropane caused increases in both in the absence or presence of S9. Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenicity for male F344/N rats receiving 62 or 125 mg/kg. For female rats there was equivocal evidence of carcinogenicity in that 250 mg/kg 1,2-dichloropropane caused a marginally increased incidence of adenocarcinomas in the mammary gland; these borderline malignant lesions occurred concurrent with decreased survival and reduced body weight gain. There was some evidence of carcinogenicity for male and female B6C3F1 mice exposed to 1,2-dichloropropane, as indicated by increased incidences of hepatocellular neoplasms, primarily adenomas. Synonym: propylene dichloride

Journal Article↗
PubMed1985

NTP Toxicology and Carcinogenesis Studies of 1,2-Dichlorobenzene (o-Dichlorobenzene) (CAS No. 95-50-1) in F344/N Rats and B6C3F1 Mice (Gavage Studies).

The major use of 1,2-dichlorobenzene is as an intermediate in the synthesis of several organic compounds (e.g. 3,4-dichloroaniline) and in the syntheses of the herbicides propanil, diuron, and neburon. It is used as an industrial solvent for toluene diisocyanate, an additive to degreasing agents, a heat exchange medium, a deodorant for garbage and sewage, an ingredient in paint removers, an engine cleaner and de-inking solvent, and a solvent and intermediate in dye manufacture). 1,2-Dichlorobenzene is also used as an insecticide and a fumigant to control peach tree borers, bark beetles, grubs, and termites and to kill mites and other insects in poultry houses and animal sleeping quarters. Because of its properties as both an insecticide and a solvent, 1,2-dichlorobenzene has been used in low-pressure aerosol formulations of insecticides. Approximately 49 million pounds of 1,2-dichlorobenzene were produced in the United States in 1980. First reported commercial production began in 1921. In 13-week studies using F344/N rats and B6C3F1 mice, 500 mg/kg of 1,2-dichlorobenzene (<99% pure) decreased survival in male and female mice and female rats when administered in corn oil by gavage five times per week. At this dose, 1,2-dichlorobenzene produced centrolobular necrosis of the liver, hepatocellular degeneration, and depletion of lymphocytes in the thymus and spleen of both sexes of rats and mice. At a dose of 250 mg/kg, necrosis of individual hepatocytes was observed in both sexes of rats and in male mice. Minimal hepatocellular necrosis was observed in a few rats at a dose of 125 mg/kg, but no hepatic alterations were observed in mice at this dose. Renal tubular degeneration was observed in male rats at 500 mg/kg, and multifocal mineralization of the myocardial fibers of the heart and skeletal muscle were seen in mice. The only hematologic changes considered notable were slight decreases in hemoglobin and hematocrit in the 500 mg/kg male and female rats and in red blood cell counts in the 500 mg/kg male rats; no other marked hematological changes were observed in either species. Two-year toxicology and carcinogenesis studies of 1,2-dichlorobenzene were conducted by administering the test chemical in corn oil gavage five times per week for 103 weeks to groups of 50 male and 50 female F344/N rats and B6C3F1 mice at doses of 60 and 120 mg/kg. Groups of 50 rats and 50 mice of each sex received corn oil by gavage on the same schedule and served as vehicle controls. Survivals of female rats, male mice, and female mice were comparable to those of the corresponding vehicle controls in the 2-year study, but survival of high dose male rats was (P<0.001) shorter than that of the vehicle controls. In this group there were three accidental deaths and five deaths probably due to the gavage process; in addition aspiration of 1,2-dichlorobenzene in corn oil into the lungs may have been a contributing factor to the deaths of 12 high dose male rats. The 120 mg/kg dose level of 1,2-dichlorobenzene did not affect body weight in rats or mice of either sex or survival of mice or female rats. An increase in tubular regeneration in the kidney of high dose male mice was observed in the 2-year study (control, 8/48, 17%; low dose, 12/50, 24%; high dose, 17/49, 35%). No other compound-related nonneoplastic histological lesions were noted in the 2-year study. The incidence of pheochromocytoma of the adrenal gland in low dose male rats was elevated (P<0.05, life table test) relative to controls (9/50, 16/50, 6/49). However, the incidence in the high dose group was lower than that of the controls and the dose-response trend was not statistically significant. Therefore, the increase in pheochromocytoma in the low dose male rats is not regarded as related to administration of 1,2-dichlorobenzene. A dose-related increase (P<0.05) in malignant histiocytic lymphoma was observed in male mice (control, 0/50, 0%; low dose, 1/50, 2%; high dose, 4/50, 8%) and in female mice (0/49, 0%; 0/50, 0%; 3/49, 6%); however, comparisons of the numbers of animals with all typnt;; 3/49, 6&percnt;); however, comparisons of the numbers of animals with all types of lymphomas is considered to be a more appropriate comparison. 1,2-Dichlorobenzene did not increase the incidence of all types of lymphomas (combined) in male mice (8/50, 16&percnt;; 2/50, 4&percnt;; 4/50, 8&percnt;) or female mice (11/49, 22&percnt;; 11/50, 22&percnt;; 13/49, 27&percnt;). Therefore, the increase in histiocytic lymphomas was discounted. Under the conditions of these two-year gavage studies, there was no evidence of carcinogenicity of 1,2-dichlorobenzene for male or female F344/N rats or B6C3F1 mice receiving 60 or 120 mg/kg per day. Levels of Evidence of Carcinogenicity: Male Rats: Negative Female Rats: Negative Male Mice: Negative Female Mice: Negative Synonym: o-dichlorobenzene

Journal Article↗
PubMed1986

NTP Toxicology and Carcinogenesis Studies of Tetrachloroethylene (Perchloroethylene) (CAS No. 127-18-4) in F344/N Rats and B6C3F1 Mice (Inhalation Studies).

Tetrachloroethylene is used primarily as a dry cleaning agent, an industrial solvent for fats, oils, tars, rubber, and gums, and a metal degreasing agent. Tetrachloroethylene had antihelminthic uses, particularly for hookworms (1.6-8 g/60 kg), and was formerly used in combination with some grain protectants and fumigants. Toxicology and carcinogenesis studies of tetrachloroethylene (99.9% pure) were conducted by inhalation exposure of groups of 50 male and 50 female F344/N rats and B6C3F1 mice 6 hours per day, 5 days per week, for 103 weeks. The exposure concentrations used (0, 200, or 400 ppm for rats and 0, 100, or 200 ppm for mice) were selected on the basis of results from 13-week inhalation studies in which groups of 10 rats and 10 mice of each sex were exposed to tetrachloroethylene at 100-1,600 ppm for 6 hours per day, 5 days per week. During the 13-week studies, 1,600 ppm tetrachloroethylene was lethal to 20%-70% of the rats and mice and reduced the final body weights of survivors. In rats, tetrachloroethylene at 200-800 ppm caused minimal to mild hepatic congestion. In dosed male and female mice, minimal to mild hepatic leukocytic infiltration, centrilobular necrosis, bile stasis (400-1,600 ppm), and mitotic alteration (200-1,600 ppm) were produced. Tetrachloroethylene exposure also caused minimal renal tubular cell karyomegaly in mice at concentrations as low as 200 ppm. During the 2-year studies, exposure to tetrachloroethylene did not consistently affect body weight gains in either rats or mice. Exposure at 400 ppm tetrachloroethylene reduced the survival of male rats (control, 23/50; low dose, 20/50; high dose, 12/50). This reduced survival may have been related to an increased incidence of mononuclear cell leukemia. Tetrachloroethylene at both exposure concentrations reduced the survival of male mice (46/50; 25/50; 32/50), whereas exposure at 200 ppm reduced female mouse survival (36/50; 31/50; 19/50). Early deaths in mice may have been related to the development of hepatocellular carcinomas. Both concentrations of tetrachloroethylene were associated with increased incidences of mononuclear cell leukemia in male rats (28/50; 37/50; 37/50). In female rats, tetrachloroethylene increased the incidence of leukemia (18/50; 30/50; 29/50) and decreased the time to occurrence of the disease. Tetrachloroethylene produced renal tubular cell karyomegaly in male and female rats, renal tubular cell hyperplasia in male rats, and renal tubular cell adenomas or adenocarcinomas (combined) in male rats (1/49; 3/49; 4/50). The incidence of the renal tubular cell tumors was not statistically significant; these uncommon tumors have been consistently found at low incidences in male rats in other 2-year studies of chlorinated ethanes and ethylenes. One low dose male rat had a kidney lipoma, and another had a nephroblastoma. Four high dose male and two high dose female rats had gliomas of the brain, whereas one control male and one control female had this tumor. In male and female mice, tetrachloroethylene caused dose-related increases in the incidences of hepatocellular neoplasms. In males, tetrachloroethylene at 200 ppm increased the incidence of hepatocellular adenomas (11/49; 8/49; 18/50) and at both concentrations increased the incidence of hepatocellular carcinomas (7/49; 25/49; 26/50). In female mice, tetrachloroethylene at both concentrations increased the incidences of hepatocellular carcinomas (1/48; 13/50; 36/50). Tetrachloroethylene also produced renal tubular cell karyomegaly in both sexes of mice, and one low dose male mouse had a tubular cell adenocarcinoma. In these inhalation studies, there were no neoplastic changes in the respiratory tracts of either species, but there was an increase in the incidence of squamous metaplasia in the nasal cavities in dosed male rats (0/50; 5/50; 5/50). Tetrachloroethylene was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 in the presence or absence of male Syrian hamster or male Sprague-Dawley rat liver S9. Tetrachloroethylene was not mutagenic in was not mutagenic in L5178Y/TK&plusmn; mouse lymphoma cells with or without metabolic activation and did not induce sex-linked recessive lethal mutations in Drosophila melanogaster. Tetrachloroethylene did not induce sister-chromatid exchanges or chromosomal aberrations in Chinese hamster ovary cells in the presence or absence of metabolic activation. An audit of the experimental data was conducted for these 2-year studies on tetrachloroethylene. No data discrepancies were found that influenced the final interpretations. Under the conditions of these 2-year inhalation studies, there was clear evidence of carcinogenicity of tetrachloroethylene for male F344/N rats as shown by an increased incidence of mononuclear cell leukemia and uncommon renal tubular cell neoplasms. There was some evidence of carcinogenicity of tetrachloroethylene for female F344/N rats as shown by increased incidences of mononuclear cell leukemia. There was clear evidence of carcinogenicity for B6C3F1 mice as shown by increased incidences of both hepatocellular adenomas and carcinomas in males and of hepatocellular carcinomas in females. Synonyms: carbon bichloride; carbon dichloride; ethylene tetrachloride; per; perc; perchlor; perchlorethylene; perchloroethylene; perk; tetrachlorethylene; 1,1,2,2-tetrachloroethylene Trade names: Ankilostin; Antisal 1; Dee-Solv; Didakene; Dow-Per; ENT 1860; Fedel-Un; Nema; Perclene; Percosolv; Perklone; PerSec; Tetlen; Tetracap; Tetraleno; Tetravec; Tetroguer; Tetropil

Journal Article↗