摘要:

Representative consumer talcums and powders, including 20 body powders, baby powders, facial talcums, and also one pharmaceutical talc, were analyzed to determine their mineralogical and chemical composition. Where known, all were formulated prior to 1973. Of the 20 products 10 contained detectable amounts of tremolite and anthophyllite, principally asbestiform, while some also contained fragmented forms of these minerals. The amounts ranged from tenths of a percent to over 14% by weight; two contained detectable amounts of chrysotile asbestos fiber. Eight contained quartz, seven ranging from 2 to 5%, with one as high as 35%. The analyses showed that the consumer products examined were rarely the pure mineral talc, but rather were mixtures of various minerals; some samples consisted of three to five minerals, only one of which was talc. Other common mineral phases included chlorite, platy serpentine, pyrophyllite, mica, and carbonate minerals. Kaolin additive was identified in two products. The single pharmaceutical talc examined contained only a trace amount of quartz.

ISSN:0098-4108    

DOI:10.1080/15287397609529432

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The toxicologic problems of today frequently require long‐term, multidisciplinary experimentation involving large numbers of animals. In order to provide the extensive safety evaluation necessary to produce data that can be reasonably extrapolated to humans, automated research support systems have transcended the position of useful tools and have become an integral part of the total design of experimental protocols. For an automated information system to fully represent the reality of the experiment, it must be able to assure integrity, as well as provide for the storage, calculation, and retrieval of data values of the quality and quantity necessary for fulfilling protocol requirements. Guarantees against error and loss of data, in addition to flexibility and easy access, must be an inherent part of the system if the acceptance and confidence of the investigator are to be obtained. This paper discusses the criteria, philosophies, and benefits of integrated data systems that ensure integrity of toxicologic research support.

ISSN:0098-4108    

DOI:10.1080/15287397609529433

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Fluoride concentrations in plasma 3 hr after a single oral dose of NaF (5 mg/100 g body weight) were increased 26 times above the control, but the concentrations in erythrocytes and red cell membranes were increased only 1.8 and 1.5 times over the respective control levels. Ionic concentrations of magnesium and calcium in erythrocytes and their membranes were significantly changed by fluoride administration, but the ionic concentrations in plasma were not statistically changed in comparison with controls. Acid phosphatase activities in plasma and erythrocytes were significantly decreased by fluoride administration, but alkaline phosphatase activity in the plasma was not changed. Mg2+‐activated ATPase activity was significantly elevated in the erythrocyte membrane by fluoride administration; (Na++ K+)‐activated A TPase activity was significantly decreased in the membrane.

ISSN:0098-4108    

DOI:10.1080/15287397609529434

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The presence of vinyl chloride monomer (VCM) in foodstuffs and its demonstrated carcinogenic potential when administered by the oral route has raised questions concerning the quantitative estimation of the safety of the use of food packaging fabricated from rigid polyvinyl chloride. A statistical model, which was tested by curve‐fitting data obtained from an oral uptake study, has been demonstrated to be of predictive value. Ninety‐five percent confidence limits were also calculated, and the data from this study were compared with those from a previous gas phase exposure study. It was concluded that if the total daily liquid intake contained 20 ppm of VCM then the area generated under the blood level‐time curve, for rats, would be equivalent to an inhalation exposure of about 2 ppm for 24 hr.

ISSN:0098-4108    

DOI:10.1080/15287397609529435

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Relatively low toxicity in the adult has been reported for the organic acid herbicides 2,4‐dichlorophenoxyacetate and 2,4,5‐trichlorophenoxyacetate (2,4,5‐T). Although small doses of these herbicides are excreted rapidly, acute impairment of renal excretion has been reported when large doses of herbicide were administered. After the administration of 2,4,5‐T in vitro analysis of renal proximal tubular function showed a decrease in the activity of the organic acid transport system which handles these herbicides. In addition, the pretreated animals show an impairment in the organic base transport system. To determine the nature of 2,4,5‐T renal depression, renal cortical slices from herbicide‐pretreated animals were studied. Alterations in the initial influx of organic ions, steady‐state accumulation, and efflux were measured. Furthermore, a specific and reversible depression of tissue oxygen consumption was demonstrated. These changes do not appear to be the result of alterations in the gross morphology, electrolyte composition, or cell water content of the renal cortex.

ISSN:0098-4108    

DOI:10.1080/15287397609529436

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The health status of 16 herds of dairy cattle exposed to low levels of polybrominated biphenyl (PBB) was compared with that of 15 control herds. Milk production of the contaminated herds was not significantly changed in 1972, 1973, and 1974 and was not significantly different from that of control herds in the same years. Mortality of adult cows and calves, the percentages of cows culled from the herds because of old age and low production, disease, or sterility, and the general health conditions were similar in the two groups. Serum concentrations of calcium, glucose, and cholesterol in contaminated herds were significantly different from those of the control herds, but the relationship to PBB exposure needs further investigation.

ISSN:0098-4108    

DOI:10.1080/15287397609529437

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Rats that received cadmium 300 ppm in drinking water (average daily cadmium intake = 4.5 mg/rat) for 12 wk attained peak cadmium levels of 112, 34, and 19 μg/g in hair, liver, and kidney, respectively, at week 4. Rats that ingested cadmium 200 ppm (average daily cadmium intake = 3.6 mg/rat) for 13 wk attained peak cadmium levels of 29 μg/g in kidney at week 7, and 94 and 27 μg/g in hair and liver, respectively, at week 9. Despite continuous exposure to the heavy metal, tissue cadmium concentrations declined to steady‐state levels of 24–33 μg/g in hair and 10–17 μg/g in liver and kidney. Histopathologic effects were not observed in liver or kidney. In contrast to cadmium in hair, blood cadmium levels, which remained consistently low (< 0.04 μg/ml) throughout the study, did not correlate with changes in cadmium levels in liver and kidney.

ISSN:0098-4108    

DOI:10.1080/15287397609529438

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Studies of the metabolic responses of rats to 0.2% dietary theophylline were conducted. Young male rats were fed theophylline‐containing diets or control diets for 8 wk and killed after 22 hr without food. Levels of serum lipids, glucose, and ketones were determined as were hepatic glycogen, lipid, calcium, magnesium, and zinc levels. Epididymal fat pad lipid content, as well as kidney cation levels and hepatic mitochondrial respiration, was also determined. Chronic theophylline feeding lowered blood glucose levels, serum triglyceride levels, hepatic lipid and calcium levels, and the state III respiration with succinate as the substrate. Kidney calcium and magnesium levels were elevated in theophylline‐fed rats as were the serum cholesterol levels. The relationship of these metabolic responses to theophylline feeding is discussed as a function of the theophylline effect on tissue cation levels.

ISSN:0098-4108    

DOI:10.1080/15287397609529439

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The usefulness of murine pulmonary defense systems as a means for assessing potential toxicity was further confirmed. Recent investigations had indicated that the effects of a chemical agent on mucociliary transport and phagocytic function comprised a sensitive indicator. As one example of such an application, because of the wide usage of proprietary colds preparations containing volatile oils, as well as the use of such oils in various industries, it is important to reassess the potential of such preparations for toxicity when new test systems become available. Mice and rats were exposed to vapors of camphor, menthol, eucalyptol, and turpentine, as contained in a commonly used colds preparation, for 4 and 8 hr prior to challenge with aerosols of radiolabeled Staphylococcus aureus. The exposure system simulated conditions present when the colds preparation is vaporized according to directions for use. Rates of pulmonary bacterial transport and inactivation, as well as of phagocytic ingestion, were determined following exposure to the colds preparation. Each of these rates was unchanged by the treatment. Thus, in this biological system exposure to therapeutic levels of the colds preparation did not impair mucociliary or phagocytic function.

ISSN:0098-4108    

DOI:10.1080/15287397609529440

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

A common feature of much scientific information reflected in government regulation is its passage directly from the laboratory into government decision without benefit of review and interpretation. This pattern can be attributed to a variety of factors. One is the incentives that lead government agencies to act quickly and conservatively in the name of protection of human health. Another is the relatively lengthy process of traditional review and interpretation via professional meetings and scientific publication. Yet, the case appears very strong for preserving, if foreshortening, the stages of peer review of otherwise unmatured data used in regulation. Several schemes of this sort have been tried in the past few years–some with apparent success. These are discussed alongside the proposal for a science court–a quasi‐Judicial vehicle for rendering judgments about scientific findings.

ISSN:0098-4108    

DOI:10.1080/15287397609529441

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor