摘要:

The choice of experimental subjects for research in neurobehavioral toxicology influences the questions that may be asked and the generality of findings obtained. In particular, the relative merits of “random bred” animals, heterogeneous stocks, selected lines, and inbred strains are discussed. Several aspects of genetic‐environmental coaction that may influence data are described, and general issues for their analyses discussed.

ISSN:0098-4108    

DOI:10.1080/15287398209530225

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Rats were supplied with 25 kinds of food, which were divided into 5 classes of protein and 5 classes of fat content, to examine the effect of dietary protein and fat on the metabolism and retention of DDT in the liver. The results suggested that dietary protein and fat changed DDT and its metabolites concentration in liver. The concentration of DDT decreases according to the increase of dietary protein content. The concentration of DDT and its metabolites in liver increases when the dietary fat content increases.

ISSN:0098-4108    

DOI:10.1080/15287398209530226

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Tetrachloroethylene (1,1,2,2‐tetrachloroethene) is a widely used organic solvent capable of producing adverse renal, hepatic, and central nervous system effects. The cardiac effects of tetrachloroethylene, thus far unexplored, were studied in several species. To standardize the dosimetry, tetrachloroethylene was prepared for intravenous injection in solutions of Tween 80, which had no demonstrable cardiotoxicity. In rabbits under urethane and in cats and dogs under pentobarbital, tetrachloroethylene increased the vulnerability of the ventricles to epinephrine‐induced extra‐systoles, bigeminal rhythms, and tachycardia. The mean threshold doses of tetrachloroethylene were 10 mg/kg in rabbits, 24 mg/kg in cats, and 13 mg/kg in dogs. In rabbits this threshold dose for cardiac arrhythmias corresponded to blood levels between 2.2 and 3.6 μg/ml. Animals demonstrating a reflex bradycardia to vasopressor doses of epinephrine were relatively resistant to the arrhythmogenic action of tetrachloroethylene. Ventricular arrhythmias occurred in less than 30% of the animals after tetrachloroethylene alone. In cats higher doses of tetrachloroethylene (40 mg/kg) produced acute pulmonary edema. Tetrachloroethylene (30–40 mg/kg) decreased left intraventricular dP/dt(max) in dogs, without significantly increasing left intraventricular end‐diastolic pressure, although there was a transient decrease in arterial blood pressure that accompanied the early phase of myocardial depression. These results are being used as the basis for studies of the chronic effects of tetrachloroethylene on cardiac performance.

ISSN:0098-4108    

DOI:10.1080/15287398209530227

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Neurotoxic effects of acrylamide, methylmercury, and 2,5‐hexanedione were studied in forty female BALB/c mice. The chemicals were dissolved in distilled water and administered via light‐tight drinking bottles. Three control groups were used. The first received distilled water, the second received concentrated saccharin solution to assess the effects of reduced water intake, and the third was maintained on a reduced food diet. Motor functions were quantified by measuring landing foot‐spread and rotarod performance. Baseline data were collected before dosing started. Mice were placed, twice weekly, on an accelerating rotarod, and their retention time was recorded. In the landing foot‐spread test, the experimenter dropped mice from 15 cm onto a flat, smooth surface once a week. The hindlimb splay was then measured by the examiner. Both experimenter and examiner were unaware of the identity of each group (except‐of the food deprived group, in the case of the experimenter) during the first exposure. Decreased retention time and increased hindlimb splay were observed in mice after 12 d of exposure to acrylamide. Recovery followed treatment cessation. Increased hindlimb splay preceded an obvious decline of rotarod performance in the group receiving the 10 ppm of methylmercury solution. Mice receiving the 20 and 40 ppm of methylmercury solutions did not display any change in these tests before overt signs of toxicity. 2,5‐Hexanedione produced a small decline in performance to a constant level after 85 d of exposure. After dosing termination, performance returned to baseline values. Control groups showed no change in performance on either the rotarod or the landing foot‐spread test. Our data show that the rotarod and hindlimb splay tests in mice are about equal in sensitivity to the effects of the neurotoxic chemicals tested.

ISSN:0098-4108    

DOI:10.1080/15287398209530228

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Male mice (25–30 g) were injected (ip) with 0, 3.5 × 10−6, or 17.5 × 10−6mol trimethyltin bromide (TMT), triethyltin bromide (TET), tri‐n‐propyltin chloride (TPT), or tri‐n‐butyltin bromide (TBT) per kg. Additional groups of mice were also injected (ip) with either 0 or 17.5 × 10−6mol sodium bromide (NaBr) or 17.5 × 10−6mol stannic bromide (SnBr4) per kg. The mice were tested with maximal electroshock seizure (MES) at 0.5, 4, 21–24, and 96 h following exposure to the organotin compounds. Mice exposed to TMT, TET, TPT, or TBT exhibited dose‐dependent decreases in MES severity as evaluated by seizure‐grade distributions and duration of tonic seizure phases. The tri‐n‐alkyltin compounds exhibited a structure‐activity relationship in their ability to decrease maximal responsiveness to the MES test. In order of decreasing ability they were: TMT > TET > TPT > TBT. Administration of NaBr and SnBr4did not alter MES responsiveness, indicating the essential role of the alkyl moieties of the tri‐n‐alkyltin compounds in producing alterations in central nervous system function.

ISSN:0098-4108    

DOI:10.1080/15287398209530229

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Male mice (25–30 g) were injected (ip) with either 0, 3.5 × 10−6, 17.5 × 10−6, or 26.25 × 10−6mol/kg of either tricyclohexyltin bromide (TCT) or triphenyltin acetate (TPhT) in a corn‐oil vehicle. The mice were tested for maximal electroshock seizure (MES) at 0.5, 4, 24, and 96 h following exposure to the organotin compounds, and the durations of seizure phases were measured and used to assess seizure severity. No significant changes in seizure‐grade distribution, as compared to controls, were observed in any of the TCT‐ or TPhT‐treated groups at any of the time points examined. No significant changes in the duration of seizure phases, as compared to controls, were observed in animals dosed with 3.5 × 10−6mol/kg of TCT or TPhT at any of the time points evaluated. At 0.5 h following exposure, the mice dosed with the two higher levels of TCT or TPhT exhibited increases in MES severity. At 4 and 24 h following exposures, the mice exposed to the two higher dose levels of TPhT exhibited decreases in MES severity, followed by a recovery of normal seizure severity at 96 h. Conversely, the animals dosed with the higher dose levels of TCT exhibited at increased MES severity at 4, 24, and 96 h following exposure. These results, in combination with those in the preceeding paper (Doctor and Fox, 1982), reveal that at equimolar doses TCT and TPhT possess a different spectrum of action than the tri‐n‐alkyltins.

ISSN:0098-4108    

DOI:10.1080/15287398209530230

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The effects of inhalation of hexachlorocyclopentadiene (Hex) up to 14 wk on the terminal bronchioles of rats and monkeys was examined by electron microscopy. Exposed rats elicited a concentration‐related increase in the incidence of electron‐lucent inclusions in the bronchiolar Clara cells when compared to controls. The inclusions in the high‐concentration (0.2 ppm) group were round and more abundant than the rod‐shaped inclusions observed in the intermediate (0.05 ppm) and low‐concentration (0.01 ppm) exposure groups. No ultrastructural changes were observed that could be attributed to the inhalation of Hex vapor in exposed monkeys. The origin and significance of these inclusions is discussed in light of the literature.

ISSN:0098-4108    

DOI:10.1080/15287398209530231

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Field corn was grown on subsoil, pH 5.5, that had been amended with 100 dry tons per acre (224 metric tons per hectare) of municipal sewage sludge from Syracuse, New York. The corn plants containing 3.88 ppm dry weight of cadmium were field‐chopped and ensiled, and the silage was fed to growing sheep for 225 d. The sheep fed the sludge‐grown corn silage showed a significantly (1) higher feed efficiency, (2) higher hepatic microsomal p‐nitroanisole O‐demethylase activity, and (3) higher concentrations of cadmium in liver and kidney and nickel in kidney as compared to the control animals. No significant treatment effects were observed in mutagenic responses for animal feed or feces samples. No consistent treatment effects were noted during histopathologic examination of sheep tissues.

ISSN:0098-4108    

DOI:10.1080/15287398209530232

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This study reports the differential neurotoxic effects of coumaphos [O,O‐diethyl O‐(3‐chloro‐4‐methyl‐7‐coumarinyl) phosphorothioate] when applied orally or dermally in the adult hen. Dermal administration of single (50–500 mg/kg) or daily (100 mg/kg) doses resulted in delayed neurotoxicity in hens, similar to that caused by other delayed neurotoxic organophosphorus compounds. Coumaphos caused loss of weight and produced ataxia, which progressed to paralysis and death. Degeneration of axons and myelin in the spinal cord was the most consistent histopathoiogic alteration and was identical to that reported for other delayed neurotoxic organophosphorus esters. Only one hen showed peripheral nerve degeneration. Oral administration of a single 100 mg/kg dose or daily doses of 10 mg coumaphos caused severe acute toxicity and killed all treated hens after 1–8 d. These hens did not develop delayed neurotoxicity. Some hens given a single oral 50‐mg/kg dose or daily 5‐mg/kg doses of coumaphos recovered from the initial cholinergic effect and developed clinical signs of delayed neurotoxicity. These hens, however, improved with time and did not show unequivocal nervous‐tissue damage at termination.

ISSN:0098-4108    

DOI:10.1080/15287398209530233

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Tri‐o‐tolyl phosphate (TOTP) was injected into the yolk sac of 120‐h chicken embryos at concentrations equivalent to 200, 100, 50, 25, or 0 (vehicle control) μg TOTP/g egg. On d 22 of incubation, all live hatchlings were wing‐banded, weighed, and housed in a brooder battery according to treatment level. Birds were examined daily for mortality as well as for development of clinical signs indicative of delayed neurotoxicity. Body weights were determined at weekly intervals for 4 wk. At the end of the fourth week, all birds were killed and necropsied. Liver, spleen, bursa of Fabricius, ovary or testes, and comb (male only) were removed and weighed. The injection of 200 μg TOTP/g egg significantly depressed hatchability when compared to controls. Chick mortality was not significantly affected by TOTP injection. Clinical symptoms characteristic of delayed neurotoxicity did not develop during the 4‐wk observation period. TOTP injection caused a transient growth depression that disappeared by 4 wk of age in both sexes. Organ weights at 4 wk of age were not consistently affected by the treatment.

ISSN:0098-4108    

DOI:10.1080/15287398209530234

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor