摘要:

Multifunctional acrylates and methacrylates (MFA) represent a class of materials with considerable chemical reactivity that are used in many applications with opportunity for contact exposure. They represent appreciable eye and skin contact hazards, and several members of the class may be absorbed from skin to cause systemic effects. A number of MFAs have been identified as sensitizers. While the acute toxicity of MFAs is certain, the effects of repeated or chronic exposure are less clear. Data are presented that suggest that MFAs are not appreciable fetotoxic or teratogenic hazards and do not elicit a strong carcinogenic response following chronic dermal exposure. The use of these data for product safety purposes and research needs is discussed.

ISSN:0098-4108    

DOI:10.1080/15287398609530916

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effects of chemical carcinogens on various aspects of cellular metabolism were measured in human IMR‐90 fibroblasts. These studies were undertaken to assess the ability of IMR‐90 cells to be used for the study of chemical carcinogenesis in vitro. It was found that (1) chemical carcinogens inhibited DNA synthesis in synchronous cultures of IMR‐90 fibroblasts; (2) the effective concentrations of carcinogens showing effects in this system were lower than for other published in vitro cell assay systems; (3) compounds that require metabolic activation to a carcinogenic form demonstrated the ability to inhibit DNA synthesis in IMR‐90 fibroblasts; (4) a fluorometric determination of aryl hydrocarbon hydroxylase (AHH) activity in IMR‐90 cells revealed a low level of inducible AHH; (5) IMR‐90 cells can metabolize 7,12‐dimethyl‐benzanthracene (DMBA) to compounds that are identified as metabolites of DMBA in vivo.

ISSN:0098-4108    

DOI:10.1080/15287398609530917

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Response‐surface methodology (RSM) techniques provide a useful statistical approach for the design and analysis of experiments involving multiple variables. Although it has been used for some time in the areas of chemical engineering and agriculture, RSM has only recently been applied to the solution of biological problems. Here we have utilized RSM to investigate the interaction of two direct‐acting, monofunctional alkylating agents [ethyl methanesulfonate (EMS) and ethylnitrosourea (ENU)] in Chinese hamster V79 cells with respect to the in vitro induction of sister chromatid exchanges (SCEs). A factorial design was employed in which the cells were exposed to the agents singly and in simultaneous combinations for 4 h. The cells were collected for SCE determination 30 h after treatment. The analysis revealed concentration‐dependent increases in SCEs for both of the agents, with ENU being the more effective on an equimolar basis. In addition, single‐ and multiple‐agent interactions were detected. The most important finding was that over the treatment range studied, a significant negative interaction occurs between EMS and ENU with regard to SCE induction. It is suggested that RSM not only may be useful in determining the statistical relevance of experimental variables but also may generate hypotheses the evaluation of which could provide additional insights into the underlying mechanisms involved.

ISSN:0098-4108    

DOI:10.1080/15287398609530918

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Polycyclic aromatic hydrocarbon (PAH) exposure can cause mixed‐function oxidase (MFO) enzyme induction in certain tissues of various organisms. Measurement of such induction might serve as a useful bioindicator of human exposure to PAHs, provided readily obtainable human tissues can be utilized for such measurements.

ISSN:0098-4108    

DOI:10.1080/15287398609530919

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effects of intravenous (iv) administration of chlordimeform (CDM) were investigated in 22‐ to 30‐d‐old pentobarbital‐anesthetized Sprague‐Dawley rats. Animals (n = 25) were given sequential iv injections of 5, 10, 30, 60, and 120 mg CDM/kg, or normal saline vehicle followed by a single injection of 60 mg CDM/kg. Heart rate (HR), arterial blood pressure (BP), and electrocardiogram (ECG) were monitored for all animals, while body temperature was maintained at control levels (37°C). CDM produced profound acute effects on all cardiovascular parameters monitored and persistent delayed effects on HR and BP. These effects were similar to but less severe than those observed in a previous study using geriatric animals. Younger animals also appeared to be more resistant to the lethal actions of CDM.

ISSN:0098-4108    

DOI:10.1080/15287398609530920

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effects of intraperitoneal (ip) administration of chlordimeform (CDM) were investigated in 22‐ to 24‐d‐old pentobarbital‐anesthetized Sprague‐Dawley rats. Animals (n = 32) received a single ip injection of CDM at either 10, 30, or 60 mg/kg, or of normal saline vehicle. Heart rate (HR) and electrocardiogram (ECC) were monitored for all animals, while body temperature was maintained at control levels (3TC). HR decreased 21–29% in the treated animals, and there were no differences observed across dose groups or over time. ECG effects were confined to rate‐related changes only. The decrease in HR produced by CDM in these animals was comparable to the delayed HR effect seen in previous studies from this laboratory, despite major differences in dosing regimens and routes of administration.

ISSN:0098-4108    

DOI:10.1080/15287398609530921

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Intracerebral injection of CH3Hg and CH3Hg complexed with glutathione (CSH), cys‐teine (cys), cysteinylglycine (cys‐gly), and homocysteine (homocys) resulted in differences in toxicity. Criteria based on neurological indices, mortality, and weight loss indicated that the cys‐gly complex of CH3Hg was significantly less toxic than CH3Hg or the other complexes. The other complexes of CH3Hg (CSH, homocys, and cys) were also found to be less toxic than CH3Hg. The selenium status of the animal did not seem to significantly influence the toxicity of CH3Hg and the complexes. While CH3Hg complexed to cys‐gly was significantly less toxic than CH3Hg alone, there were no differences observed in the CH3Hg half‐life values or in the distribution of these compounds in the kidneys, brain, liver, and blood. It was observed, however, that the CH3Hg‐cys‐gly complex had higher fecal excretion on d 3 and 4 following intracerebral injection.

ISSN:0098-4108    

DOI:10.1080/15287398609530922

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In a previous study from this laboratory, chlorine dioxide (ClO2) treated drinking water depressed thyroxine (T4) levels in the African green monkey. The present study again demonstrated a decrease in T4levels in the same species after 4 wk of oral exposure. However, after 8 wk of treatment T4levels rebounded to above pretreatment levels, coinciding with an increase in thyroid radioiodide uptake. This T4rebound phenomenon and increased iodide uptake may be due to a compensatory endocrinological mechanism. In rats, T4levels dropped during the 8‐wk ClO2treatment period in a dose‐dependent manner, and no rebound effect was observed. Iodide uptake values in the rat were not affected. It appears that ClO2may have an effect on thyroid function in both species.

ISSN:0098-4108    

DOI:10.1080/15287398609530923

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The in vitro cultivation of murine spleen cells with MnCl2resulted in the enhancement of natural killer (NK) cell activity as measured in a 4‐h51Cr‐release assay. Optimal enhancement of NK activity was observed at concentrations of 70–20 μg MnCl2/culture (72–144 μM Mn2+). Enhancement of NK activity by MnCl2was not associated with any changes in the number or viability of cells following culture. The addition of antiasialo GM1, antibody and complement to spleen cell cultures completely abrogated the enhancement of NK activity by MnCl2. The enhancement of NK activity by MnCl2in vitro was accompanied by interferon induction. The addition of rabbit anti‐mouse interferon to spleen cells cultured with MnCl2reduced NK activity. NK activity in cultures treated with MnCl2was also reduced upon removal of plastic adherent cells. However, restoration of enhanced NK activity by addition of adherent cells to nonadherent cells in the presence of MnCl2was not observed. Similar effects of NK activity were observed with polyinosinic‐polycytidylic acid (Poly I · C), a known interferon inducer and NK enhancer. The results demonstrate that murine splenic NK activity is enhanced in vitro by MnCl2and that this enhancement may be mediated by interferon induction. The results also suggest that in vitro enhancement of NK activity by MnCl2, as with Poly I · C, may require participation of an adherent cell population for NK augmentation.

ISSN:0098-4108    

DOI:10.1080/15287398609530924

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

To better understand the potential health risks associated with short‐term NO2exposures, a study was conducted to examine the effects of single and repeated NO2exposures on the clearance of inert tracer particles from the alveolar region of rabbit lungs. Single 2‐h exposures to 0.3, 1.0, 3.0, and 10.0 ppm produced a concentration‐related acceleration in alveolar particle clearance, which resulted in greater particle removal when compared to control. The greatest response was produced at the lower NO2levels, where as much as 40% more particles were cleared when compared to control. Fewer particles were cleared following a 10.0‐ppm NO2exposure when compared to the lower NO2levels, and there were indications from the clearance pattern that the higher level was beginning to slow clearance, although an actual retardation was not found. Repeated 14‐d exposures (2 hid) to 1.0 or 10.0 ppm NO2produced a response similar to a single exposure at the same concentration, suggesting a certain degree of adaptation was produced after the initial exposures. Possible mechanisms for these differences in clearance patterns are discussed. The results of this study demonstrated altered alveolar clearance following short‐term NO2exposure at environmentally relevant concentrations; changes in this important host defense mechanism may be indicative of some underlying pathologic condition.

ISSN:0098-4108    

DOI:10.1080/15287398609530925

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor