Criteria for evaluating the clinical and practical utility of models used by nurses

Arguably, nursing, like all health care disciplines, is an applied science. Essentially, this refers to the application of theory in order to understand and respond to the health problems of clients. These theories may be drawn (borrowed) from any applied science, or generated inductively from clinical nursing practice. Alternatively, nurses may attempt to apply deductive theory (global theoretical frameworks) known as nursing models. In this paper, all theoretical approaches, irrespective of origin, are referred to as models used by nurses. Thirteen criteria by which clinicians, and others, can evaluate the clinical and practical utility of models used by nurses which are expressed in the form of questions are identified and discussed. The criteria are an extension, both in detail and in number, of those developed by Reynolds and Cormack and subsequently applied by those writers to the Johnson Behavioural System Model of Nursing. The value, or otherwise, of individual models, or of models in general, will not be discussed in this paper. However, the authors propose that if the evaluation criteria described here are applied to existing models, serious deficits will be identified in relation to their clinical and practical utility.     

RNA structure, not sequence, determines the 5' splice-site specificity of a group I intron.

The group I self-splicing introns act at exon-intron junctions without recognizing a particular sequence. In order to understand splice-site selection, we have developed an assay system based on the Tetrahymena ribozyme to allow the study of numerous 5'-splice-site variants. Cleavage at the correct site requires formation of the correct secondary structure and occurs most efficiently within a 3-base-pair window centered on base pair 5 from the bottom of the P1 stem. Within this window the ribozyme recognizes and cleaves at a "wobble" base pair; the base pair above the cleavage site also influences splicing efficiency. The recognition of RNA structure rather than sequence explains the ability of these transposable introns to splice out of a variety of sequence contexts.     

The effect of minimal interventions by general practitioners on long-term benzodiazepine use.

Seventy one long-term users of benzodiazepines were asked by their general practitioners in a letter or short interview to reduce their medication. Twenty two patients were successful in giving up or reducing their consumption to less than 100 tablets per annum. There were no clear predictors of success in terms of patient characteristics, duration of drug use, type of benzodiazepine, reason for drug use or strategy employed to reduce medication. However, patients who were successful at reducing their medication had a significantly lower mean baseline drug consumption than unsuccessful patients. The implications of this study are that a proportion of long-term users who are not in current crisis, especially those with relatively low consumption, can reduce or stop benzodiazepine treatment with minimal difficulty.