Volume/outcome relationships in small rural hospitals.

This article summarizes a study of relationships between hospital volume and patient outcomes for diagnoses commonly treated and procedures commonly performed in smaller rural hospitals. Literature review findings and results of analyses using secondary data for several conditions suggest few if any volume/outcome relationships (with mortality being the main outcome for which data were available). A basic finding of the study is that most conditions and procedures for which volume effects on mortality have been found typically do not pertain to small rural hospitals. However, the available secondary data are weak, and many conditions and procedures have not been studied for small rural hospitals. Therefore, continued monitoring and review are important, as well as improved data systems, further research, and information dissemination on volume/outcome relationships. In particular, examining relationships between volume and outcomes in addition to mortality is critical to a thorough understanding of this topic.

Analytic framework for evaluation of telemedicine.

This paper discusses two conceptual models intended to facilitate research on the effects and effectiveness of telemedicine. The first is a conceptual framework to study the efficacy of telemedicine as a diagnostic medium. Using conditions that are carefully chosen to serve as indicators of effectiveness, we recommended the analysis of sensitivity and specificity to establish the accuracy of telemedicine in relation to conventional health care delivery. Suggested guidelines for interpretation of the results are discussed. The second model is a scheme for classification of telemedicine applications that is based on processes of care rather than on specialties or disorders. The purpose of this classification scheme is to facilitate research on such variables as costs, access, acceptability, and effects on practice patterns.

Effects and effectiveness of telemedicine.

The use of telemedicine has recently undergone rapid growth and proliferation. Although the feasibility of many applications has been tested for nearly 30 years, data concerning the costs, effects, and effectiveness of telemedicine are limited. Consequently, the development of a strategy for coverage, payment, and utilization policy has been hindered. Telemedicine continues to expand, and pressure for policy development increases in the context of Federal budget cuts and major changes in health service financing. This article reviews the literature on the effects and medical effectiveness of telemedicine. It concludes with several recommendations for research, followed by a discussion of several specific questions, the answers to which might have a bearing on policy development.

Histidine regulation of cyclic AMP metabolism in cultured renal epithelial LLC-PK1 cells.

L-Histidine and imidazole (the histidine side chain) significantly increase cAMP accumulation in intact LLC-PK1 cells. This effect is completely inhibited by isobutylmethylxanthine (IBMX). Histidine and imidazole stimulate cAMP phosphodiesterase activity in soluble and membrane fractions of LLC-PK1 cells suggesting that the IBMX-sensitive effect of these agents to stimulate cAMP formation is not due to inhibition of cAMP phosphodiesterase. Histidine and imidazole but not alanine (the histidine core structure) increase basal, GTP-, forskolin-, and AVP-stimulated adenylate cyclase activity in LLC-PK1 membranes. Two other amino acids with charged side chains (aspartic and glutamic acids) increase AVP-stimulated but neither basal- nor forskolin-stimulated adenylate cyclase activity. This suggests that multiple amino acids with charged side chains can regulate selected aspects of adenylate cyclase activity. To better define the mechanism of histidine regulation of adenylate cyclase, membranes were detergent-solubilized which prevents histidine and imidazole potentiation of forskolin-stimulated adenylate cyclase activity and suggests that an intact plasma membrane environment is required for potentiation. Neither pertussis toxin nor indomethacin pretreatment alter imidazole potentiation of adenylate cyclase. IBMX pretreatment of LLC-PK1 membranes also prevents imidazole to potentiate adenylate cyclase activity. Since IBMX inhibits adenylate cyclase coupled adenosine receptors, LLC-PK1 cells were incubated in vitro with 5'-N-ethylcarboxyamideadenosine (NECA) which produced a homologous pattern of desensitization of NECA to stimulate adenylate cyclase activity. Despite homologous desensitization, histidine and imidazole potentiation of adenylate cyclase was unaltered. These data suggest that histidine, acting via an imidazole ring, potentiates adenylate cyclase activity and thereby increases cAMP formation in cultured LLC-PK1 epithelial cells. This potentiation requires an intact plasma membrane environment, occurs independent of a pertussis toxin-sensitive substrate and of products of cyclooxygenase, and is inhibited by IBMX. This IBMX-sensitive pathway does not involve either inhibition of cAMP phosphodiesterase activity or a stimulatory adenosine receptor coupled to adenylate cyclase.