Transfection-mediated expression of a dominant cAMP-resistant phenotype in the opossum kidney (OK) cell line prevents parathyroid hormone-induced inhibition of Na-phosphate cotransport. A protein kinase-A-mediated event.

Sodium-phosphate cotransport in the PTH-responsive opossum kidney (OK) cell line is inhibited by PTH, cAMP, and activators of protein kinase C. In order to probe the role of cAMP, we stably transfected OK cells with an expression vector for a cAMP-binding mutation of the murine protein kinase A regulatory subunit. Two-dimensional electrophoresis of cAMP-binding proteins from transfected cells indicated a 20-fold overexpression of the mutant regulatory unit. Protein kinase A from these cells had a 20-fold increase in the concentration of cAMP required for half-maximal activation, 2.8 microM vs. 0.15 microM for wild type cells. In the transfected cells, Na-phosphate cotransport was insensitive to up to 1 mM 8-Br-cAMP and 1 microM PTH, while these same agonists caused a significant inhibition of transport in the wild type cells. The effects on Na-phosphate cotransport of the protein kinase C activators oleoyl-acetyl glycerol and tetradecanoyl-phorbol acetate, which were marked in the wild type cells, were still present, although attenuated, in the transfected mutants. With prolonged passage, the cAMP-insensitive phenotype reverted to wild type cAMP sensitivity despite continued selection for the cotransfected neo marker. The revertant cells had a normal cAMP requirement for half-maximal activation of protein kinase A, 0.13 microM, and the PTH and cAMP-sensitive inhibition of Na-phosphate cotransport was restored. We suggest that an intact and normally cAMP-sensitive protein kinase A pathway is an absolute requirement for PTH inhibition of Na-phosphate cotransport in the OK cell.

Erotomania revisited: from Kraepelin to DSM-III-R.

Erotomania, the persistent delusion of being loved from afar by another person, has defied easy categorization for years. Kraepelin and de Clérambault both discussed the syndrome in detail, but it has recently appeared officially for the first time, in DSM-III-R, as a subtype of delusional (paranoid) disorder, in a return to the original Kraepelinian formulation. The author reviews the history, theories of etiology, course, and treatment of erotomania. He concludes that the DSM-III-R classification is correct and that neuroleptics and enforced separation, although only moderately effective, are the best treatments for troublesome cases.

Validity and reliability of a new device to simulate upper extremity work demands.

The device validity, intra-test reliability, and test-retest reliability of the LIDO WorkSET(TM) (Loredan Biomedical, West Sacramento, California) was studied. Subjects were 30 healthy incumbent workers at a manufacturing and warehousing facility. The results of this study demonstrate a very high degree of device validity in terms of torque measurements, power, and work. In addition, the test protocols were found to be reliable on an intra-test and inter-test basis. Finally, inter-test comparisons were found to be stable over time.