Primary and secondary control over age-related changes in physical appearance.

Beliefs about appearance-related changes due to aging were used to test the effects of perceived control and secondary control (acceptance) in a sample of 412 young, early-middle-age, and late-middle-age college-educated adults. Mean difference in aging-related appearance control and hypotheses regarding the adaptiveness of primary and secondary control were examined. Primary control over aging-related appearance was lower in older adults and secondary control was higher. In addition, the results indicated support for the Primacy/Back-Up Model that primary perceived control is important at all levels of actual control. Those with stronger beliefs in their primary control were less distressed. Secondary control served a back-up function in that it was related to less distress only for those who had medium or lower beliefs in primary control. The implications of these findings, that primary control may be advantageous even in low-control circumstances, are discussed.

Cholecystokinin receptors and PANC-1 human pancreatic cancer cells.

The gastrointestinal peptide cholecystokinin (CCK) has been shown to stimulate growth of human pancreatic adenocarcinoma in vitro and in vivo, although CCK receptors have not been identified in pancreatic cancer cells. The purpose of this study was to characterize the CCK receptors in pancreatic cancer cells and to correlate the receptor binding studies with the trophic action of CCK agonists and antagonists. With the use of homogenates of PANC-1 human pancreatic cancer cell line grown in culture, the binding of 125I-labeled CCK octapeptide (125I-CCK-8) was examined under various conditions to characterize the CCK receptor. Specific and saturable binding of 125I-CCK-8 was detected in PANC-1 cells; data were consistent with a single binding site. Scatchard analysis yielded a binding affinity [dissociation constant (Kd)] of 2.8 nM and a binding capacity of 26 fmol/mg protein. Binding was dependent on protein concentration, time, temperature, the presence of protease inhibitors, and pH and was sensitive to Na+, K+, Mg2+, and ethylene glycolbis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. Competition experiments indicated that L-365,260, a selective CCK-B (gastrin) receptor antagonist, was the most potent displacer of 125I-CCK-8, and no significant displacement of binding was found with the selective CCK-A receptor antagonist. Growth of PANC-1 cells in culture was stimulated by CCK at a concentration consistent with the Kd, and CCK-stimulated growth was inhibited by the CCK-B receptor antagonist (L-365,260) not the CCK-A receptor antagonist (L-364,718).(ABSTRACT TRUNCATED AT 250 WORDS)