Antecedent therapy versus detection bias as causes of neoplastic multimorbidity

Neoplastic multimorbidity occurs when a patient is found to have a second primary cancer after the occurrence of a first. The phenomenon may be the result of aging, chance, or other specific causes, but in recent years, the radio- or chemotherapy administered for the first cancer has regularly been suspected as a possible cause of the second. A commonly disregarded alternative explanation, however, is that the second cancers were clinically "silent" discoveries found because of increased diagnostic detection procedures in patients known to have a first cancer. Such patients are more likely to receive intensive surveillance and technologic testing than the general population often used as a control group. In 43 recent reports of neoplastic multimorbidity, however, only five mentioned the problem of detection bias, and only one tried to eliminate it by using a suitable analytic comparison. Unless adequate analytic precautions are taken, antineoplastic therapy may be falsely accused of being carcinogenic.

Gas-phase ionic reactions: dynamics and mechanism of nucleophilic displacements

Nucleophilic displacement reactions (the SN2 reaction) of ions in the gas phase are a prototypical reaction system that allows a study of dynamics, mechanisms, and structure-energy relations. This article reviews aspects of the kinetics (especially the applicability of statistical reaction rate theory), the relation of structure and reactivity, and the effects of small numbers of solvent molecules on the reaction and compares the behavior of the ionic reaction in the gas phase with that in solution.

Theory development and its relevance for nursing

If the nursing profession is to continue to make advancements, it must envision new ways of perceiving the phenomena peculiar to nursing and must propose meaningful explanations for these perceptions. The approaches to nursing theory development are spread out over a theory practice continuum, ranging from Martha Roger's pure scientific approach to Dickoff and James' practice approach. The very existence of this continuum signifies nursing's problem in deciphering the nature of the relationship between nursing theory and nursing practice. While the development of nursing theory is essential to the establishment of a theoretical body of knowledge unique to nursing as a science, this must not be its only function. Theory development must be integrated with nursing practice if the profession is to survive and grow.