摘要:

A review of the biodistributionand foxicityof the insect repellentN,N‐diethyl‐m‐to‐luamide (DEET) is presented. Workers using repellent containing this compound may be exposed to greater than 442 g in 6 mo. In human studies, variable penetration into the skin of from9 to 56% ofatopically applied dose and absorption into the circulatory system of approximately 77% have been reported. Excretion of DEET by humans was initially rapid but not as complete as in animal models. Only about one‐half of the absorbed DEET was excreted by humans over 5 d. Depot storage of DEET in the skin was also documented. Skin irritant effects, including scarring bullous dermatitis in humans, were reported. One animal study that reported embryotoxicity could not be confirmed by other investigators. The limited testing for mutagenicity and carcino‐genicity provided negative results. Neurotoxic effects were observed in workers exposed to 4 g or more per week. Six young girls developed encephalopathies after exposure to unspecified amounts of DEET ranging from small to massive doses. Three of these girls later died. The cause of their death has not been resolved. Because of the lack of information, further research into the absorption, carcinogenicity, and neurotoxic effects is needed.

ISSN:0098-4108    

DOI:10.1080/15287398609530891

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The compound lindane (γ‐hexachlorocyclohexane) has been used to study the ontogeny of metabolism in the developing Fischer 344 rat. The distribution and metabolic fate of lindane at 2, 9, 16, and 23 d of age was investigated following subcutaneous administration of lindane at 20 mg/kg containing 0.5 μCi [U‐14C]lindane in peanut oil. Croups of 10 pups (5 male and 5 female) were sacrificed at 4‐h intervals during the 24‐h period following dosing. Adrenals, blood, brain, heart, lung, liver, and kidneys were analyzed for radioactivity. Urine samples were analyzed for radioactivity and metabolites of lindane. There was a significant age‐dependent increase in the metabolism of lindane in the rat. High levels of radioactivity in the lung and increased reductive dechlorination suggest that the lung may play a greater role in metabolism of lindane by young rats. Oxidative phase I reactions increased significantly, while anaerobic reductive dechlorination of lindane to 4‐chlorophenylmer‐capturic acid decreased significantly with age. Phase II sulfate and glutathione conjugations decreased significantly and glucuronide conjugation increased significantly with age. Metabolism and excretion of lindane appear to parallel development of the hepatic enzymes involved in phase I and phase II reactions.

ISSN:0098-4108    

DOI:10.1080/15287398609530892

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This study was designed to test the value of a multiparameter approach in evaluating perturbations in bone marrow and peripheral blood elements of mice exposed to ethylene oxide (EtO). Mice exposed to 255 ppm EtO for 6 hid were removed for analysis after 1, 2, 4, 8, and 14 d (sequential exposure) and 4, 6, 8, and 10 wk (5 d/wk). Prior to sacrifice, blood was removed from the orbital sinus for blood cell counts, hemoglobin determination, and hematocrit. A blood film was made for differential leukocyte counts. Bone marrow was flushed from femurs and tibias and counted, and aliquots were used for stem‐cell assay (CFU‐S) or flow cytometry (FCM) analysis. One aliquot of marrow was stained with propidium iodide for cell‐cycle analysis and another was reacted with fluorescein‐conjugated monoclonal antibody for B‐cell analysis. The preparations were analyzed for forward and 90° scatter and fluorescence on an Ortho 50H cytofluorograph. Perturbations of peripheral leukocytes occurred after one exposure. After multiple exposures, hematocrit, red‐cell number, and hemoglobin were generally depressed, with transient compensatory bursts, and bone marrow cellularity and CFU‐S were below normal. However, white‐cell numbers fluctuated dramatically during the exposure period. There was a shift in differential toward granulocytes, at times resulting in severely depressed numbers of lymphocytes in the peripheral blood. The FCM analysis showed an early depletion of granulocytes in the bone marrow followed by replacement and a relative lymphocyte deficit, especially pronounced at 10 wk. The B‐cell changes reflected general lymphocyte perturbations. Shifts in numbers of cells in S and CIM were observed, consistent with a moderate bone marrow response to cell loss.

ISSN:0098-4108    

DOI:10.1080/15287398609530893

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Benzene levels in human breath and in ambient air were compared in the urban area of San Francisco (SF) and in a more remote coastal pristine setting of Stinson Beach, Calif. (SB). Benzene analysis was done by gas chromatography‐mass spectroscopy (CC‐MS). Ambient benzene levels were sevenfold higher in SF (2.6 ± 1.3 ppb,n = 25) than SB (0.38 ± 0.39 ppb, n =21). In SF, benzene in smokers’ breath (6.8 ± 3.0 ppb) was greater than in nonsmokers’ breath (2.5 ± 0.8 ppb) and smokers’ ambient air (3.3 ± 0.8 ppb). In SB the same pattern was observed: benzene in smokers’ breath was higher than in nonsmokers’ breath and ambient air. Benzene in SF nonsmokers’ breath was greater than in SB nonsmokers’ breath. Marijuana‐only smokers had benzene breath levels between those of smokers and nonsmokers. There was little correlation between benzene in breath and number of cigarettes smoked, or with other benzene exposures such as diet. Of special interest was the finding that benzene in breath of SF nonsmokers (2.5 ± 0.8 ppb) was greater than that in nonsmokers ambient air (1.4 ± 0.1 ppb). The same was true in SB, where benzene in nonsmokers breath was greater than ambient air (1.8 ± 0.2 ppb versus 1.0 ± 0.1 ppb on d 1 and 1.3 ± 0.3 ppb versus 0.23 ± 0.18 ppb on d 2). This suggests an additional source of benzene other than outdoor ambient air.

ISSN:0098-4108    

DOI:10.1080/15287398609530894

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A comparative study was conducted to contrast the hepatotoxicity of several chemicals in the musk shrew(Suncus murinus) versusother common laboratory species (mouse or rat), and the following results were obtained from serum enzymes (SCOT and SCPT) and histopathological findings of liver specimens. (1) The sensitivity ofSuncusliver toCC/4was different from that of mouse liver. (2) The sensitivity ofSuncusliver to β‐D‐galactosamine was weaker than that of rat liver. (3) The sensitivity ofSuncusliver to ethanol was stronger than that of mouse liver. Afterasingle oral administration of ethanol (99.5% vlv,0.7ml/50 g body weight), the gallbladder ofSuncusbecame enlarged and dark blue in color. (4) A striking fatty degeneration was seen 24 h after a single ip administration of amethopterin at 50 mg/kg inSuncusliver.

ISSN:0098-4108    

DOI:10.1080/15287398609530895

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The chicken embryo, brine shrimp(Artemia salina)and selected bacteria(Staphylo‐coccus epidermidis, Micrococcus flavus, andBacillus subtilis)were evaluated as alternative test systems for the determination of paralytic shellfish poisoning toxicity (saxitoxin). Dose levels ranging from 0.045 to 0.3 \ig were administered to the developing embryo through the air cell at either 0 or96h following incubation. Embryos dosed96h after incubation were the most sensitive, with 100% mortality at the 0.11‐μgdose level 24 h following exposure. Embryo mortality was 42% at to 0.3‐μg dose level when the toxin was administered at 0 h. Some embryonic malformations were observed in the 0‐h treatment group. Brine‐shrimp larvae were sensitive to saxitoxin at a dose level of5μg. A dose response based on mortality was apparent only 48 h after dosing. Limited growth inhibition was observed with the bacteria tested at concentrations between 0.0035 and 0.35 μglwell.

ISSN:0098-4108    

DOI:10.1080/15287398609530896

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This study was designed to investigate the effect of different doses of ethanol on the morbidity, mortality, and distribution of mercury in the tissues of groups of rats treated orally once daily with methyl mercury chloride (MMC: 5 mglkg · d) for 10 consecutive days. Ethanol potentiated the toxicity of methyl mercury in terms of neurological manifestations (hindleg crossings and abnormal gait) and mortality. The magnitude of effect depended on the concentration of ethanol administered. The concentration of mercury in the kidney and brain also increased with the dose of ethanol given. These findings indicate that epidemiologic studies designed to evaluate methyl mercury toxicity must take into account the multiple environmental burdens that can affect the population cumulatively and simultaneously.

ISSN:0098-4108    

DOI:10.1080/15287398609530897

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This study was initiated because of a suspected increase in incidence of lung cancer in antimony smelter workers in England. Three groups of 8‐mo‐old Wistar‐derived rats (90 males and 90 females per group) were exposed by inhalation to either Sb2O3[time‐weighted average (TWA) 45 mg/m3], Sb ore concentrate (TWA 36 + 40 mg/m3), or filtered air (controls) for 7 h/d, 5 d/wk, for up to 52 wk and sacrificed 20 wk after terminating exposures. Serial sacrifices (5 rats/sex/group) were performed at 6, 9, and 12 mo. Autopsies and histopathological examinations were performed on all animals. The dusts and animal tissues were analyzed for Sb, arsenic, and other inorganic elements by atomic absorption and proton‐induced X‐ray emission methods. The most significant findings were the presence of lung neoplasms in 27% of females exposed to Sb2O3and 25% of females exposed to Sb ore concentrate (p < 0.01). None of the male rats in any group or the female controls developed lung neoplasms. There were no significant differences in incidences of cancer of other organs between exposed and control rats. These results were compared with other published results, including an animal inhalation study with Sb2O3in which lung tumors were also induced

ISSN:0098-4108    

DOI:10.1080/15287398609530898

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Studies of the acute inhalation toxicity of lithium combustion aerosols were undertaken to aid in evaluating the health hazards associated with the proposed use of lithium metal in fusion reactors. A system was developed to generate lithium combustion aerosols by sweeping vapor from molten lithium metal into a controlled air atmosphere. Male and female F344ILov rats, 9–12 wk of age, were exposed once for 4 h to concentrations of 2600, 2300, 1400, or 620 mg/m3of aerosol (MMAD= 0.69 μm, σg= 1.45) that was approximately 80% lithium carbonate and 20% lithium hydroxide to determine the acute toxic effects. Fourteen‐day LC50 values (with 95% confidence limits) of 1700 (1300–2000) mg/m3for the male rats and 2000 (1700–2400) mg/m3for the female rate were calculated. Clinical signs of anorexia, dehydration, respiratory difficulty, and perioral and perinasal encrustation were observed. Body weights were decreased the first day after exposure in relation to the exposure concentration. In animals observed for an additional 2 wk, body weights, organ weigh ts, and clinical signs began to return to preexposure values. Histopathologic examination of the respiratory tracts from the animals revealed ulcerative or necrotic laryngitis, focal to seg‐mental ulcerative rhinitis often accompanied by areas of squamous metaplasia, and, in some cases, a suppurative bronchopneumonia or aspiration pneumonia, probably secondary to the laryngeal lesions. The results of these studies indicate the moderate acute toxicity of lithium carbonate aerosols and will aid in the risk analysis of accidental releases of lithium combustion aerosols.

ISSN:0098-4108    

DOI:10.1080/15287398609530899

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effect of various organic metal compounds on δ‐aminolevulinic acid dehydratase (ALAD, porphobilinogen synthetase) activity has been studied. Various organic tin and lead compounds have little effect on this enzyme. However, triethyl lead chloride has a potency similar to that of inorganic lead nitrate in inhibiting ALAD both forin vitrostudy and afterin vivodosing. Liver and blood ALAD have a similar sensitivity to lead compounds, which is reduced in the presence of zinc. Trimethyl lead chloride inhibits ALADin vitroto a lesser extent. The results suggest that amphiphilic organic lead compounds may directly inhibit ALAD without prior degradation to inorganic lead. The diffusibility and persistence of triethyl lead combine to make it an especially hazardous lead compound

ISSN:0098-4108    

DOI:10.1080/15287398609530900

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor