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Biomedical subjects

J ADAMS

Publications and source records attributed to J ADAMS.

11 recordsLinked to original sources
PubMed1959

Effects of calcium lack on action potential of motor axons of the lobster limb.

The effects of external calcium deprivation on certain characteristics of the action potential of the lobster motor axon have been studied. Upon exposure to calcium-free solution the spike amplitude is rapidly decreased within a few minutes and is followed by a slow linear decline. The rates of spike rise and fall are proportionally reduced more than the spike but follow similar time courses during calcium lack. Associated with these phenomena are the loss in the normal slow spike repolarization process, the development of a large and lengthy undershoot, and the appearance of a high degree of refractoriness. The mean increase in the refractory period is 525 per cent upon 10 minutes' exposure to calcium-free solution. These effects are completely reversible upon returning the axons to normal solution. These results are compared to similar effects of calcium deprivation on frog myelinated axons and squid and lobster giant axons recently observed by other workers.

Action Potentials↗
PubMed1956

The immunological specificity of type II Pneumococcus and its separation into partial specificities.

The specificity of Type II pneumococcus determined by its capsular polysaccharide (S II) may be separated into three partial specificities, each characteristic of one of the three component sugars of S II, namely, glucuronic acid, glucose, and rhamnose. By far the largest portion of antibodies in Type II antipneumococcus horse sera which cross-react with carbohydrates containing one or more of these sugars are reactive with those characterized by multiple groupings of glucuronic acid. This confirms, extends, and explains earlier observations. In confirmation of predictions based upon existing information tamarind seed polysaccharide (jellose), in which much of the glucose exists as 1,4,6-branch points, was found to react in Type II antisera. Several instances are given of cross-reactions in these antisera apparently due to the L-rhamnose component of the reacting polysaccharides. The antisera contain far more antibody capable of precipitating with substances with multiple units of glucuronic acid than with those so far tested containing multiple 1,4,6-branch points of glucose or multiple groupings of rhamnose. The long known increase of titer of gum arabic on partial hydrolysis is now fully explained and discussed, and a chemical picture is given of the change in "avidity." The sum of the partial specificities measured does not equal the whole. Quantitative data illustrating these points are given.

Cross Reactions↗