摘要:

Forty‐seven Hartley guinea pigs were exposed for 1 h to approximately 1‐μm (mass median aerodynamic diameter) sulfuric acid aerosols at concentrations that ranged from 1.2 to 48.3 mg/m3. Ten animals (controls) were exposed to filtered room air only. Eight H2SO4‐exposed animals exhibited marked increases in total pulmonary resistance and marked decreases in dynamic compliance. Four of these eight “responsive” animals died during exposure. All other H2SO4‐exposed animals exhibited no major differences from controls and were termed nonresponsive. The proportion of responsive to non‐responsive animals increased with exposure concentration, but the magnitude of pulmonary function change was similar for all responsive animals regardless of concentration. Compared to nonresponders, responsive animals had higher preexposure values of tidal transpulmonary pressure excursions and total pulmonary resistance and lower values of dynamic compliance. Preexposure transpulmonary pressure excursions were positively correlated with minute volume only for nonresponsive animals; transpulmonary pressure excursions were positively correlated with total pulmonary resistance in responsive animals. The results suggest that the Hartley guinea pig reacts to inhaled H2SO4with an essentially all‐or‐none airway constrictive response and that an animal's sensitivity to this response may be related to its preexposure airway caliber.

ISSN:0098-4108    

DOI:10.1080/15287398109529985

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Condensation aerosols of benzo/a/pyrene (BaP) with particle sizes ranging from 0.1 to 2 μm (aerodynamic diameter) were produced and studied. These aerosols were generated in a glove box by direct vaporization of BaP and homogeneous condensation of the vapor. The aerosol concentration ranged from 50 to 700 μg/l with aerosol production rates up to 15 mg BaP per minute. The effects of vaporization temperature and flow rate of diluting air on the particle size distribution and aerosol output were studied. The BaP aerosol was produced with relatively constant mass concentration and particle size distribution for more than 5 h. The aerosol was physicochemically and thermally stable. Data on thein vitrodissolution of BaP particles in aqueous solvents and in different dissolution systems suggested that the organic BaP particle does not dissolve in simple aqueous solvents. Proteins, surfactants, or ethyl alcohol enhanced the rate of dissolution of BaP. The rate of dissolution of BaP particles was inversely proportional to particle size.

ISSN:0098-4108    

DOI:10.1080/15287398109529986

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The effect of long‐term occupational exposure to CS2on various endocrinologic parameters was studied in 15 exposed men and 16 age‐matched controls. Duration of exposure varied between 10 and 36 yr. The CS2concentrations in the viscose rayon plant have been below the Finnish threshold limit value of 30 mg/m3(10 ppm) under normal operating conditions for the past 10 yr. Before this the exposure was considerably greater. Of the various endocrinologic parameters, serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) were significantly increased in the exposed group, seven workers having values above the reference limit. This was taken as a sign of primary gonadal insufficiency, which was considered only latent as serum testosterone values were unaffected. No changes were seen in serum prolactin values before or after stimulation with thyrotropin releasing hormone (TRH). No disturbance was seen in thyroid function as evaluated by serum thyroxine (T4), free thyroxine index (FTI), triiodothyronine (T3), and the thyrotropin response to TRH. Serum cortisol was also unchanged. These results may reflect high exposure during past decades rather than exposure to the present low CS2concentrations.

ISSN:0098-4108    

DOI:10.1080/15287398109529987

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The effect ofin vivoO3exposure on the mobility of pulmonary alveolar macrophages (PAM)in vitrowas investigated. Eight randomly selected rats were exposed for 4 h. Four rats were exposed to a dean air (sham) atmosphere, and four to an atmosphere containing 1 ppm O3. PAM were obtained by lung lavage and placed on gold‐colloid coated coversllps. The area cleared of gold particles by migrating PAM after 24, 48, and 72 h was used as an indicator of cell mobility. The number of PAM recoverable by lavage was similar for both groups (2 × 105), but the percentage of macrophages that made tracks was significantly smaller with 95% certainty in the O3group. For sham‐exposed and O3‐exposed groups, the area cleared by PAM increased as the length of incubation increased, with the area cleared by the sham‐exposed group being about 50% greater during each time period. When the two groups were compared statistically at each time point, the probability that they differed was, in each case, greater than 95%. It was concluded that thein vitromigrational potential of PAM was most likely decreased byin vivoexposure to O3.

ISSN:0098-4108    

DOI:10.1080/15287398109529988

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

To determine whether vitamin E (dl‐α‐tocopherol) supplementation could protect against short‐term respiratory responses to O3exposure its effects were investigated in young healthy adult volunteers. Experimental groups received 800 or 1600 IU vitamin E per day for 9 or more wk, while control groups received placebo. Subjects were then exposed for 2‐h periods to 0.5 ppm O3, with secondary stresses of heat and intermittent light exercise. Responses to O3exposure, evaluated in terms of symptoms, forced expiratory performance, and single‐breath nitrogen washout, were not significantly different between vitamin E and placebo groups.

ISSN:0098-4108    

DOI:10.1080/15287398109529989

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Yields of chemical constituents such as tar, nicotine, CO, and HCN defined by smoking machines are commonly assumed to provide a reasonable indication of the relative hazard associated with smoking a given brand of cigarette. Results reported here suggest that this assumption should be carefully reexamined.

ISSN:0098-4108    

DOI:10.1080/15287398109529990

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Ciliostasis times of the water‐soluble smoke fraction of the University of Kentucky 1R1 Reference Cigarette and experimental cigarettes were compared in the hamster tracheal ring system. Dose‐responsc relations were critically examined, and the assumptions of a dilution bioassay were tested. The model in which a logarithmic transformation was used for both mean time to ciliostasis and smoke sample concentration gave the most satisfactory linear fit. At appropriate concentrations, the ciliostatic responses of the test tobacco smokes were found to be parallel to those of the 1R1, supporting the validity of the dilution bioassay assumptions. Details of experiments and analyses are presented as examples of some of the steps required to establish valid bioassay systems.

ISSN:0098-4108    

DOI:10.1080/15287398109529991

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A series of experimental designs aimed at collecting and analyzing ciliostasis data in the most efficient and statistically valid manner was examined. The design that proved best for assessing water‐soluble tobacco smoke samples In the hamster tracheal ring system utilized two dose levels of the University of Kentucky 1R1 reference cigarette (which functions as a reference as well as a continuing check on the dose‐response relation in each experiment) plus several test tobacco smoke samples, each at a single dose level. A pair of animals formed the basis of a randomized block design, with one of the technician X sample preparation degrees of freedom confounded with animal differences within a pair. Assessment of the test samples can thus be expressed in terms of potency relative to the 1R1 reference. Control chart procedures were an essential facet of the system. Details of experiments and methods of data analysis are presented as examples of some of the steps required to establish valid bioassay systems.

ISSN:0098-4108    

DOI:10.1080/15287398109529992

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Teratogenicity and fetotoxicity of secalonic acid D, a toxic fungal metabolite produced byPenicillium oxalicum, were investigated with pregnant CD1 mice. The compound was administered ip on d 7–15 of pregnancy. A dose‐dependent reduction in weight gain of mothers receiving all doses of secalonic acid D and an increase in resorptions of implanted embryos of dams treated with more than 5 mg/kg secalonic acid D occurred. The latter effect was nearly 100% at 15 or 9 mg/kg given in NaHCO3with or without dimenthyl sulfoxide (DMSO), respectively. A corresponding decrease in the percent of live fetuses and a decrease in the average fetal body weight on d 19 of pregnancy also occurred. Multiple gross, skeletal, and visceral anomalies were noted in fetuses born to mothers receiving 10 mg/kg or more in NaHCO3containing DMSO. In NaHCO3alone, the minimum teratogenic dose was 6 mg/kg. Major malformations included cleft palate, cleft lip, open eyelids, missing phalangeal ossification centers, and shortened mandibles. The results indicated that secalonic acid D is embryocidal and teratogenic as well as fetotoxic when given to female CD1 mice during pregnancy.

ISSN:0098-4108    

DOI:10.1080/15287398109529993

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Diets containing 10% ground apricot kernels were fed to young and breeding male and female Sprague‐Dawley rats. The kernels were obtained from 35 specific apricot cultivars and divided into groups containing low amygdalin (less than 50 mg cyanide per 100 g), moderate amygdalin (100–200 mg cyanide per 100 g), or high amygdalin (more than 200 mg cyanide per 100 g). Growth of young male rats was greatest in the low‐ or moderate‐amygdalin group which may indicate only that they were more sensitive to the bitter taste of the kernels with high amygdalin contents. In female rats, but not males, liver rhodanese activity and thiocyanate (SCN) blood levels were increased with the high‐amygdalin diet, but both male and females efficiently excreted thiocyanate, indicating efficient detoxication and clearance of cyanide hydrolyzed from the dietary amygdalin. No changes in blood chemistry were observed. Although parturition and 3‐d survival indices were poor in pups from dams fed a basal semisynthetic diet, offspring of breeding rats fed the high‐amygdalin diet for 18 wk had lower 3‐d survival indices, lactation indices, and weaning weights than those in the low‐amygdalin group. This may indicate that the cyanide present In the milk may not be efficiently detoxified to SCN and excreted by neonates.

ISSN:0098-4108    

DOI:10.1080/15287398109529994

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor