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Biomedical subjects

W H Lewis

Publications and source records attributed to W H Lewis.

At least 109 records · Page 6Linked to original sources

Focused antigen capture immunoassay.

A new approach is described to immunoblotting in which antigens after isoelectric focusing are capture on nitrocellulose membranes coated with a specific antibody. The method has been applied to the analysis of human IgA kappa and lambda from whole blood and serum without prior purification. The visualized bands were quantified by laser densitometry in four pI ranges. It is concluded that, under the conditions used, close to 100% of serum IgA is captured. The method has a coefficient of variation of 4.5-12.8%, mean 8.0%.

Antigen-Antibody Reactions↗

Distribution and incidence of North American pollen aeroallergens.

Using standardized aerosampling procedures, ambient pollen samples were collected at 15 locations in six regions of North America. The results provide baselines for examining human exposure to inhalant pollen allergens throughout the year on a broad geographic scale. In eastern temperate areas, pollen shed was closely linked to plant flowering seasons, with trees releasing pollen in the spring, grasses in the early summer, and weeds in the later summer and fall. Variations to this fundamental pattern were observed to the south and west; understanding these differences is essential if atopic persons suffering from allergic symptoms are to be assisted. For example, highly diverse tree pollen was found in North Carolina and Georgia for prolonged periods at high levels. These data suggest that a more sensitized population in the southeastern United States manifests allergic symptoms longer. Further south and southwest, pollen was captured throughout the year and sometimes at unexpected times. For instance, bimodal releases of grass pollen in both the spring and fall allow dual exposures of atopic persons, extending possible hypersensitivity to multiple seasons. Enhancing pollen exposure further, our data show limited overall variation in morning and afternoon levels, implying a continuous absorption of all major pollen types during daylight hours.

Air Pollution↗

Ritualistic use of the holly Ilex guayusa by Amazonian Jívaro Indians.

In Amazonian Peru and Ecuador leaf decoctions of the rainforest holly Ilex guayusa with high caffeine concentrations are used as a morning stimulant. After daily ingestion, ritualistic vomiting by male Achuar Indians, better known as Jívaros, reduces excessive caffeine intake, so that blood levels of caffeine and biotransformed dimethylxanthines do not cause undesirable CNS and other effects. Emesis is learned and apparently not due to emetic compounds.

Caffeine↗