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Biomedical subjects

A N Rohl

Publications and source records attributed to A N Rohl.

30 records · Page 2Linked to original sources
PubMed1976

Consumer talcums and powders: mineral and chemical characterization.

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, pyrophyllitem mica, and carbonate minerals. Kaolin additive was identified in two products. The single pharmaceutical talc examined contained only a trace amount of quartz. The chemical composition of these products, including both major oxide and trace element content, correlated with their mineral components. Four samples contained substantial concentrations of nickel, cobalt, and chromium, suggesting latice substitution or the presence of trace mineral phases. Geological provenance of the talcs may be ascertained on the basis of chemistry. Possible adverse health effects from intermittent use of these products, especially those that contain asbestiform and fragmented anthophyllite and tremolite, chrysotile, quartz, and trace metals, are presently unknown and warrnat evaluation.

Asbestos↗
PubMed1975

Exposure to asbestos in the use of consumer spackling, patching, and taping compounds.

Analysis of representative samples of spackling, patching, and jointing compounds, purchased at retail stores in the New York City area, has shown that some contain asbestos minerals as well as other biologically active substances. Measurements suggest that home repair work involving the use of such materials may result in exposure to dust at concentrations sufficient to produce disease.

Asbestos↗
PubMed1974

Asbestos in talc.

Talc deposits include asbestos minerals such as chrysotile and amphiboles that may be carried over into consumer products. Optical microscopy and x-ray diffraction analyses may not reveal their presence. Examples are given of electron microscopy procedures that permit detection and measurement.

Asbestos↗
PubMed1974

Identification and quantitation of asbestos in talc.

The currently used analytical methods for identification, characterization and quantitation of asbestos fiber in consumer talcum products include polarized light microscopy, x-ray diffraction analysis, transmission electron microscopy with selected area electron diffraction and electron microprobe techniques. Light microscope methods have severe limitations imposed by the ultimate size resolution of the light-optical system. Small particles go unresolved; those marginally resolved may possess optical properties different from those properties cited in the literature; most optical properties, e.g., indices of refraction, are difficult to measure on small particles. In addition to these difficulties, talc fibers often possess optical properties different from those of talc plates, which further confound analysis. Light microscopy is recommended for use only as a preliminary tool on limited, large-sized, samples. Transmission electron microscopy is a good standard technique for visualization of contaminant asbestos fibers. Together with selected area electron diffraction, talc fibers may be easily differentiated from amphibole asbestos fibers on the basis of both morphological and structural characterization. Chrysotile fibers are easily distinguished on this basis as well. The amphibole asbestos minerals require chemical characterization to differentiate among the different fiber types. Probe analysis is mandatory for such fibers. The major drawbacks to electron beam instrumentation for the mineralogical characterization of talcum products are the time and effort required for data acquisition. These techniques do not lend themselves to routine study.X-ray diffraction analysis, utilizing the step-scan method, offers a relatively rapid, quantitative technique for gross fiber analysis. Based on comparison with standard specimens the fiber content of talcs may be quantitatively determined. It is essential to employ a specimen preparation technique which yields homogeneously dispersed particles. Tremolite may be determined at levels as low as 0.10% by weight, chrysotile 0.25%, and anthophyllite at 2.0% by weight occurrence in talc. The variance of these values depends upon many factors, including the mass absorption coefficient of the fiber types as compared to talc and selected diagnostic reflections and their relative intensities. Each of the above techniques is described in detail. A method for routine analysis of consumer talcum products is suggested.

Asbestos↗
PubMedDate not supplied

Biological activity in vitro of chrysotile compared to its quarried parent rock (platy serpentine).

Crushed serpentine rock, quarried at Rockville, Maryland, has been used in large quantities for road and playground surfacing. The rock consists essentially of the fibrous serpentine mineral chrysotile (asbestos) and platy serpentines. In vitro bioassay in P338D1, a malignant mouse macrophage-like cell line, show that chrysotile is cytotoxic while the platy serpentines are not.

Animals↗
PubMedDate not supplied

Port Allegany Asbestos Health Program: a community response to a public health problem.

The Port Allegany Asbestos Health Program (PAAHP) is a unique, community-run program that resulted from the successful cooperative efforts of a labor union, a corporation, community health care providers, and a medical school. PAAHP's goal is to develop a permanent community health organization that will use the most advanced existing knowledge to mitigate the adverse health effects anticipated as a result of the use of amosite asbestos in a Port Allegany, Pa. factory. All 1,188 persons employed by the factory during the years 1964-72 and the 3,000-4,000 persons in household contact with them are eligible for the program. PAAHP's major services are intensive medical surveillance, smoking cessation assistance, health education for participants, and continuing education for area physicians about asbestos-related diseases. One of the program's policies is not to disturb the usual patterns of medical care. If further testing or treatment is needed, patients are referred to their usual personal physicians. PAAHP does not provide ordinary medical care or medical insurance. Across the nation, the number of workers estimated to have been exposed to asbestos is more than 20 million, and their household contacts are estimated to be about three to four times that number. Adverse health effects resulting from asbestos exposure include elevated risk of lung cancer, mesothelioma, gastrointestinal tumors, and asbestosis. The problem requires the development of public health solutions. PAAHP has demonstrated the feasibility of a community-based model as one useful approach.

Asbestos↗