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Biomedical subjects

C S Wheeler

Publications and source records attributed to C S Wheeler.

10 recordsLinked to original sources
PubMed1996

Increased 5-lipoxygenase metabolism in the lungs of human subjects exposed to ozone.

The environmental pollutant ozone, at sufficiently high levels, is known to induce pulmonary inflammation with resultant airway obstruction in normal subjects. Eicosanoids comprise one group of mediators released from alveolar macrophages which are involved in the pathogenesis of inflammatory lung diseases. We compared the effects of 2-h exposures to 0.4 ppm ozone and filtered air on pulmonary function and eicosanoid levels in bronchoalveolar lavage fluid in 11 normal healthy volunteers. Subjects were exposed to a 6-fold increase in minute ventilation using an adjusted work load on a cycle ergometer. All subjects complained of cough and dyspnea, and demonstrated increased airway obstruction, and increased specific airway resistance following ozone exposure as compared to air exposure. Bronchoalveolar lavage cell count demonstrated a 9-fold increase in the number of neutrophils with a lesser reduction in the number of alveolar macrophages following ozone exposure. Notably, bronchoalveolar lavage fluid leukotriene (LT) C4 (8-fold) and to a lesser extent LTB4 (1.5-fold) levels were higher following ozone exposure compared to air control, with no change in prostaglandins. In a subset of four subjects, alveolar macrophage arachidonic acid metabolism was studied in vitro following separate in vivo exposures to both ozone and air. Alveolar macrophages obtained following ozone exposure released more 5-lipoxygenase (1.5-fold) metabolites, with no change in cyclooxygenase metabolites, than did cells obtained following air exposure. These observations document activation of the 5-lipoxygenase pathway in the lung following ozone exposure, and suggest that alveolar macrophages may participate in the generation of LT, whose actions promote airway inflammation and obstruction.

Adolescent↗
PubMed1990

Cellular, biochemical and functional effects of ozone: new research and perspectives on ozone health effects.

Ozone, a toxic component of photochemical oxidant air pollution, has been the focus of considerable research efforts for several decades. In spite of this large body of work, questions remain as to the potential risks to human health represented by chronic low-level exposure to ozone. Newer studies in animals have provided fundamental information on the range of biochemical, functional and morphologic responses to ozone exposure. While the response to ozone exposure is extremely complex, some generalities have emerged which may aid attempts to apply the results of these studies to decisions regarding the protection of human health.

Animals↗
PubMed1990

Exposure to man-made mineral fibers: a summary of current animal data.

The inhalation of asbestos fibers (crocidolite, chrysotile and amosite) has been implicated in the development of a number of lung disorders including lung cancer, asbestosis, and mesothelioma. The mechanism responsible for these effects is not well characterized but is generally thought to be related to the fibrous nature of these materials. Therefore, concerns have also been raised as to the potential health impact of other fibrous materials including man-made mineral fibers. Man-made mineral fibers are being used as substitutes for asbestos in a wide range of products. However, relatively little data are available on the potential health impact of these fibrous materials. Epidemiology and clinical studies have served as an important source of information on the effect of various environmental pollutants, but have not been sufficient to date to fully address the potential health impact of man-made mineral fibers. This is due in part to the relatively recent introduction of a number of these materials, the long latency period before the onset of clinical symptoms, and in general, the lower exposure levels associated with these materials. Therefore, a number of animal studies have been performed to predict or confirm the toxicity of various man-made mineral fibers in humans. Both fibrosis and mesothelioma have been induced in experimental animals exposed to man-made mineral fibers although no disease has been consistently observed in occupationally exposed workers.2+ While little is known about the mechanism of this response, information from animal and cell culture experiments indicate that dose, fiber dimension, and fiber durability are the most important factors in determining the biological activity of these materials.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1985

Digital venous anatomy.

The veins of the digits and their valves were studied in nine cadaveric hands by sequential angiography, microdissection, routine histology, cross-sectional microradiography, and corrosion casting. The findings revealed a pattern of dorsal venous arches situated over each digit. Connections between those arches were at the level of the metacarpal heads, the point at which most of the palmar venous blood joins the dorsal system by intercapitular veins. A system of valves, which were arranged so as to direct flow from distal to proximal, from palmar to dorsal, and from radial to ulnar in the hand, was present in all veins as far distal as the pulp.

Fingers↗
PubMed1980

Binding of 125I-physalaemin to rat parotid acinar cells.

1. The binding of [125I]physalaemin to rat parotid acinar cells was investigated. 2. The [125I]physalaemin exhibited a small degree of specific binding that was rapid, reversible and saturable. 3. The EC50 values for inhibition of binding by four peptides were well correlated with their ability to activate Ca-dependent K release from the rat parotid gland. 4. The number of binding sites, which may represent substance P receptors, was estimated to be in the range of 200/cell, a value quite different from those reported previously for muscarinin (840/cell) or alpha-adrenergic (15,000/cell) receptors. 5. It is concluded that if, as previously suggested, these receptors regulate the same population of Ca channels, then the mechanism or perhaps efficiency by which this is achieved may differ for the three receptors.

Animals↗
PubMed1976

Renal artery stenosis after renal transplantation.

Renal artery stenosis occurred in eight of fifty patients who received a renal transplant during a three year period. The evaluation and management of these cases is summarized. Trauma associated with kidney procurement, preservation, or arterial anastomosis as well as the rejection process itself may contribute to the development of these lesions. Arteriography may be indicated at an earlier stage in patients who respond poorly to medical treatment of repeated episodes of "rejection."

Adult↗