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Biomedical subjects

W F Gutknecht

Publications and source records attributed to W F Gutknecht.

9 recordsLinked to original sources
PubMed2001

Sources of variability in collection and preparation of paint and lead-coating samples.

Chronic exposure of children to lead (Pb) can result in permanent physiological impairment. Since surfaces coated with lead-containing paints and varnishes are potential sources of exposure, it is extremely important that reliable methods for sampling and analysis be available. The sources of variability in the collection and preparation of samples were investigated to improve the performance and comparability of methods and to ensure that data generated will be adequate for its intended use. Paint samples of varying sizes (areas and masses) were collected at different locations across a variety of surfaces including metal, plaster, concrete, and wood. A variety of grinding techniques were compared. Manual mortar and pestle grinding for at least 1.5 min and mechanized grinding techniques were found to generate similar homogenous particle size distributions required for aliquots as small as 0.10 g. When 342 samples were evaluated for sample weight loss during mortar and pestle grinding, 4% had 20% or greater loss with a high of 41%. Homogenization and sub-sampling steps were found to be the principal sources of variability related to the size of the sample collected. Analysis of samples from different locations on apparently identical surfaces were found to vary by more than a factor of two both in Pb concentration (mg cm-2 or %) and areal coating density (g cm-2). Analyses of substrates were performed to determine the Pb remaining after coating removal. Levels as high as 1% Pb were found in some substrate samples, corresponding to more than 35 mg cm-2 Pb. In conclusion, these sources of variability must be considered in development and/or application of any sampling and analysis methodologies.

Child↗
PubMed1984

New techniques for imaging and analyzing lung tissue.

The recent technological revolution in the field of imaging techniques has provided pathologists and toxicologists with an expanding repertoire of analytical techniques for studying the interaction between the lung and the various exogenous materials to which it is exposed. Analytical problems requiring elemental sensitivity or specificity beyond the range of that offered by conventional scanning electron microscopy and energy dispersive X-ray analysis are particularly appropriate for the application of these newer techniques. Electron energy loss spectrometry, Auger electron spectroscopy, secondary ion mass spectrometry, and laser microprobe mass analysis each offer unique advantages in this regard, but also possess their own limitations and disadvantages. Diffraction techniques provide crystalline structural information available through no other means. Bulk chemical techniques provide useful cross-checks on the data obtained by microanalytical approaches. It is the purpose of this review to summarize the methodology of these techniques, acknowledge situations in which they have been used in addressing problems in pulmonary toxicology, and comment on the relative advantages and disadvantages of each approach. It is necessary for an investigator to weigh each of these factors when deciding which technique is best suited for any given analytical problem; often it is useful to employ a combination of two or more of the techniques discussed. It is anticipated that there will be increasing utilization of these technologies for problems in pulmonary toxicology in the decades to come.

Environmental Pollutants↗
PubMed1983

Acute toxicity of lead particulates on pulmonary alveolar macrophages. Ultrastructural and microanalytical studies.

Although it is well established that respiratory uptake of lead-containing particles plays a substantial role in the epidemiology of plumbism, relatively little is known about the role of the pulmonary alveolar macrophage in lead poisoning. An in vitro system was designed to investigate the effects of lead oxide particles of respirable size on the rabbit alveolar macrophage. The studies were concerned with the intracellular solubility of PbO and Pb3O4 and changes in fine structure attributable to lead toxicity. The distribution of phagocytosed lead and its intracellular reprecipitation complexes was established by electron microprobe analysis and secondary ion mass spectroscopy in conjunction with transmission electron microscopy, scanning electron microscopy, scanning transmission electron microscopy, and backscatter imaging. It was found that Pb3O4, PbO and PbO-coated particles were ingested by the rabbit alveolar macrophages and that each of these lead oxide compounds produced similar damage to the fine structure of the cell. Swelling of the mitochondria, nuclear membrane, and endoplasmic reticulum was common, as well as were characteristic reprecipitation complexes of lead, phosphorous, and calcium within the nuclear heterochromatin and cytoplasm of the cell. The precipitation complexes were not seen in cells incubated with the particles if phagocytosis was blocked by 0.22-microns, membrane filters. It was concluded that phagocytosis of these lead oxide particles was necessary to produce the cytopathic changes. It is suggested that solubilization of lead from the ingested particles in phagosomes of macrophages results in the liberation of intracellular lead with the resultant formation of reprecipitation complexes.

Animals↗
PubMed1977

Investigations of black bronchoalveolar human lavage fluid.

The removal by bronchoalveolar lavage (two occasions) of 10(11) black macrophages containing crystals of aluminum silicate, large amounts of amorphous carbon, and oxidized lipids was followed by considerable improvement in gas exchange in a patient. Sixty-eight percent of these pulmonary macrophages were viable and normal, as judged by chemotatctic and phagocytic activity. Except for cigarettes, no source for the previously mentioned ingested foreign substances was found. These observations suggest that removal by lavage of nonviable macrophages laden with foreign bodies from distal portions of the lungs of pulmonary patients may be therapeutically useful.

Carbon↗
PubMed1975

Proton-induced x-ray emission analysis--a promising technique for studying the metal content of plants and soils.

The ease of employing proton-induced X-ray emission analysis (PIXEA) to studies relating metal content of soils to metal uptake in plants was aptly demonstrated in an investigation concerning the effect of automotive pollution on the abundance of about 16 elements accumulated in ribwort plantain and its surrounding soil. Elemental concentrations were shown to be dependent on the age of the plant leaves, as well as the distance from the roadside.

Metals↗
PubMed1975

Levels of toxic metals in marine organisms collected from Southern California coastal waters.

Emission of toxic trace metals into southern California coastal waters has resulted in the extensive accumulation of the elements within marine sediments. The current study was undertaken to evaluate concentrations of trace metals in bottom-dwelling marine fauna collected from two sampling areas. Analyses carried out on muscle samples of the dover sole (Microstomus pacificus) and the crab (Cancer anthonyi) by proton-induced x-ray emission analysis showed considerable concentrations of arsenic and selenium. Samples of gonads, digestive gland, and muscle from the crab Mursia gaudichaudii analyzed by atomic absorption spectroscopy showed elemental concentrations in muscle similar to the crab Cancer anthonyi and much higher metal levels in gonad and digestive gland. These findings suggest the need for further studies concerning the relationship between emission of metals into the marine environment and their abundance in marine fauna.

Animals↗