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Biomedical subjects

C Ingerman

Publications and source records attributed to C Ingerman.

10 recordsLinked to original sources

Downward comparison, prejudice, and evaluations of others: effects of self-esteem and threat.

In two studies, we explored the effects of trait self-esteem and threats to the self-concept on evaluations of others. In Study 1, subjects high, moderate, and low in self-esteem received either success, failure, or no feedback on a test and later evaluated three pairs of targets: in-groups and out-groups based on a minimal intergroup manipulation, those who scored above average and those who scored below average on the test, and themselves and the average college student. Study 2 explored the effects of self-esteem and threat on in-group favoritism in a real-world setting, campus sororities. Together, the results of these studies indicate that individuals high in self-esteem, but not those low in self-esteem, respond to threats to the self-concept by derogating out-groups relative to the in-group when the group boundaries have evaluative implications.

Achievement

A model system for studying initial events in atherosclerosis.

A model system has been developed which employs the central artery of the rabbit ear, and allows for the study of 1) ultra-structural changes in the arterial endothelium and 2) formation and release of prostacyclin and thromboxane from the arteries in situ. Use of the model should be helpful in evaluating the initial events in atherosclerosis. Both prostacyclin and thromboxane (detected by radioimmunoassay) were formed by arteries in situ in response to infusion of sodium arachidonate.

Animals

Persistence of thromboxane A2-like material and platelet release-inducing activity in plasma.

During the incubation of arachidonic acid with platelet-rich plasma, a persistent activity appeared that caused the release of [14C]5-hydroxytryptamine from indomethacin-treated platelets. By the time-course of its appearance and disappearance, this release-inducing activity could be dissociated from prostaglandin endoperoxides and associated with thromboxane A2-like material. This material persists in plasma because of its continued production and increased stability.

Arachidonic Acids

Formation of an intermediate in prostaglandin biosynthesis and its association with the platelet release reaction.

A compound that could be converted to prostaglandin F(2alpha) by mild chemical reduction was formed by human platelets in response to arachidonic acid, collagen, or L-epinephrine. It was present in maximal amounts at about 1 min after addition of arachidonic acid or collagen to platelet-rich plasma. Its initial formation appeared to precede platelet aggregation by these agents and was closely correlated with the release of adenine nucleotides and radioactive 5-hydroxytryptamine from platelets. Moreover, the compound was itself found outside the platelets. This compound is probably an endoperoxide intermediate in prostaglandin biosynthesis and may be a trigger for the platelet release reaction.

Adenine Nucleotides

Formation of prostaglandins during the aggregation of human blood platelets.

Prostaglandins E(2) and F(2alpha) were formed in response to ADP, L-epinephrine, or collagen by human platelets suspended in plasma containing citrate anticoagulant and stirred at 37 degrees C. The prostaglandins formed by platelets in response to collagen were rapidly released and the amounts formed were proportional to the amount of collagen added. The formation of the prostaglandins was associated with the single wave of aggregation induced by collagen or the second wave of aggregation induced by epinephrine. The above findings are discussed with reference to published studies on the biochemical changes occurring during platelet aggregation. It is suggested that the formation and release of prostaglandins is associated with the secretion of endogenous ADP and 5-hydroxytryptamine.

Adenosine Diphosphate