Calmodulin (CaM) has been reported to have affinity for the estrogen receptor (ER). Observations reported here reveal a direct physical interaction between purified CaM and ER. This direct ER-CaM interaction may be an initial event preceding the assembly of ER plus auxiliary proteins into the active ER complex with its DNA motif, the estrogen response element. We demonstrate that CaM is an integral component of this complex by using a system reconstituted from purified ER and nuclear extract from ER-negative breast cancer cells and also with ER-depleted nuclear extract of an ER-positive breast cancer cell line. Although CaM is essential for formation of this complex, it is not sufficient, suggesting roles also of auxiliary proteins. CaM also is functionally required for activation of an ER-responsive promoter, in the 17␤-estradiol-ER pathway of hormone action and regulation of 17␤-estradiol-responsive gene expression that is associated with proliferation of mammary epithelial cells. CaM1 plays a pivotal role in the proliferation of a variety of cells. Several observations indicate CaM involvement in estrogen regulation of breast cancer cell growth. Calcium homeostasis is lost (1), and expression of calcium binding proteins is modulated (2-4). There is an overall increase of Ca 2ϩ levels in human mammary tumors (5, 6), and CaM concentrations are 2-3-fold higher in estrogen receptor-positive (ERϩ) than in estrogen receptor-negative (ERϪ) breast tumors (7). The growth of breast cancer cells is highly sensitive to anti-calmodulin drugs (8, 9), and the anti-estrogen Tamoxifen binds to CaM with high affinity and antagonizes its action (10). CaM also modulates estrogen (17␤-estradiol (E2)) binding to ER (11), and synergistic inhibition of growth by CaM inhibitors and antiestrogens (12, 13) are associated with breast cancer.Both anti-estrogens and anti-calmodulin drugs block breast cancer cells at an identical point in the G 1 phase of the cell cycle (14). Furthermore, CaM is known to stimulate the phosphorylation of estrogen receptors (15). Biochemical evidence suggests an interaction of CaM with ER (11, 16 -19), but these results did not demonstrate a direct physical contact.We examined more directly the possibility of a role of CaM in key downstream events of E2 action, i.e. the interaction of ER protein with its cognate DNA sequence (estrogen response element (ERE)) to form the ER⅐ERE complex and the resulting transactivation of an E2-responsive promoter. We observed that CaM directly interacts with ER, and is not only an integral component of the ER⅐ERE complex but also plays an essential role in complex formation. Its functional involvement in the molecular pathway of E2-induced transactivation of hormoneresponsive genes in breast cancers was tested. EXPERIMENTAL PROCEDURESCell Lines and Culture-MCF-7 and MDA-MB-231 cell lines were obtained from ATCC and were grown in rich medium (Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, 2.8 M hydrocortisone, 1 g/ml insulin, and 12.5 ng/ml epide...

Patients after cardiac surgery experience moderate to severe pain in the immediate postoperative period as a result of surgical interventions, such as incision, sternotomy, sternal retraction, pericardiotomy, tissue dissection, and the presence of chest tubes. 1 Poorly controlled acute pain increases suffering, cardiovascular stress, and respiratory complications and may develop into persistent postoperative pain, which adversely affects patients' daily activities, psychological well-being, and quality of life. 2

The rare and potentially fatal complication of asystole during direct laryngoscopy is linked to direct vagal stimulation. This case describes asystole in an 85-year-old female who underwent suspension microlaryngoscopy with tracheal dilation for subglottic stenosis. Quick recognition of this rare event with immediate cessation of laryngoscopy resulted in the return of normal sinus rhythm. This incident emphasizes the implications of continued vigilance during laryngoscopy and the importance of communication between the anesthesia and surgical staff to identify and treat this rare complication. The case was successfully concluded by premedication with an anticholinergic and by increasing the depth of anesthesia.