Principal/agent theory and decision making in health care

Principal/agent theory, an economics concept that defines an agency relationship as "a contract under which one or more persons engage another person (the agent) to perform some service on their behalf which involves delegating some decision-making authority to the agent," is held to be applicable to the patient/physician relationship, in contrast to the view that this is a fiduciary relationship, not a contractual one. The distinction between fiduciary and contractual relationships is illuminated in the process of evaluating objections to the application of the principal/agent theory to the patient/physician relationship. The ability of the principal/agent theory to reveal important features of advance directives, understood as public documents rather than as confidential instructions from patient to physician, is also examined.     

A novel hsp70-like protein (P70) is present in mouse spermatogenic cells.

Mouse spermatogenic cells contain relatively large amounts of a 70-kilodalton protein (P70) that is closely related to hsp70, the major inducible heat shock protein. When hsp70 from spermatogenic cells is heat induced, it migrates to the same location as does P70 on two-dimensional polyacrylamide gels, indicating that it has an apparently identical mass and isoelectric point. P70 reacts strongly and specifically with an anti-Drosophila hsp70 monoclonal antibody that is specific for products of the hsp70 gene family. Both P70 and hsp70 are also ATP-binding proteins and are purified by using ATP-affinity chromatography. However, P70 and hsp70 are unique proteins on the basis of peptide map analysis and are regulated differently in germ cells. P70 appears to be a novel heat shock protein of spermatogenic cells which is synthesized in association with germ cell differentiation.     

In vitro detachment of bacteria from ruminal digesta by buffered sodium oleate solutions

The effectiveness of a buffered sodium oleate solution was evaluated for detaching bacteria from ruminal digesta samples. A response surface derived from an octagonal design was used to determine the pH and concentration combination for maximum detachment of total and cellulolytic bacteria. The total number of bacteria detached increased up to 81% over control with treatment of a pH 8.8 and 1.5% sodium oleate solution. The recovery of cellulolytic bacteria was decreased to 35% of control with treatment of a pH 9.0 and 0.1% sodium oleate solution. Attempts to improve the recovery of viable bacteria exposed to sodium oleate solutions were unsuccessful. This response surface design identified an optimal pH and concentration that were consistent with existing information regarding detachment of total bacteria, and suggested that sodium oleate, at the concentrations tested, was toxic to the cellulolytic population of the rumen.     

Species-specific TNF induction of thymocyte proliferation

Summary Recombinant murine (rMu) tumor necrosis factor (TNF), in a standard comitogenic assay with phytohemagglutinin, induced murine thymocyte proliferation, while up to 10,000-fold higher concentrations of recombinant human TNF did not. The induction of thymocyte proliferation was dependent upon TNF concentration in a biphasic manner. Thus, 100 to 1000 units/ml TNF were near optimal while concentrations 1,000 units/ml caused apparent down regulation. The effect was abrogated by neutralizing antibody to rMu-TNF but not by neutralizing antibody to rMu-interleukin 1 or . The rMu-TNF did not induce proliferation of the mature murine T-helper cell line, D10.G4.1, in the presence of mitogen. Taken together the results indicate that TNF, in a strictly species-specific manner, can regulate thymocyte proliferation independently of interleukin 1.Supported in part by Asahi Chemical Industry Co., Inc. and by USPHS Grants CA-24538, CA-15142 and CA-09072 awarded by the National Cancer Institute, Department of Health and Human Services     

Copper deficiency depresses rat aortae superoxide dismutase activity and prostacyclin synthesis

Prostaglandin synthesis shows dependence on lipid hydroperoxides and resultant oxygen derived radical formation. In view of the importance of dietary copper in cytosolic copper dependent superoxide dismutase (Cu/Zn SOD) activity and the role of SOD in oxygen radical formation, the influence of dietary copper on prostacylin (PGI2) synthesis and SOD activity in rat aorta was examined. Copper deficient (0.5 micrograms Cu/g diet) rats showed a significant 47% reduction in PGI2 synthesis rates by aortic ring incubations in comparison to copper adequate (6.0 micrograms Cu/g diet) animals. Aortic SOD activity was reduced by 46% in copper deficiency in comparison to copper adequate animals. Marginal dietary copper (1.6 micrograms Cu/g diet) significantly reduced aortic SOD activity by 32% but was without effect on aortic ring incubation PGI2 synthesis. These results indicate that dietary copper deficiency, and the resultant decrease in SOD activity, depresses aortic PGI2 synthesis.     

Genetic information could be integrated extrinsically for simplest life forms

Polynucleotides and proteins coupled in mutual synthesis are widely believed to have been needed for the origin of life, but this theory encounters grave problems. Simple catalysts reproducing by positive feedback, sometimes advocated as an alternative, lack a built-in mechanism for generating and accumulating genetic information. Modern organisms, however, integrate genetic information by extrinsic in addition to intrinsic mechanisms, and extrinsic mechanisms were available even at the beginning of chemical evolution for any self-reproducing entities that might have appeared. Novel molecules were generated by reactions among prevailing molecules, and a catalyst multiplying by positive feedback would have transmitted structural information not only to progeny molecules of its kind, but to derivatives and by-products. New molecules derived immediately or remotely from successfully reproducing catalysts would be favored to have catalytic properties. New catalysts with effective positive feedback would increase autocatalytically and be integrated with others into a metabolizing system by natural selection.