Theoretical calculation of relative binding affinity in host-guest systems.

The relative free energy of binding the anions Cl- and Br- to the macrotricyclic receptor SC24 in water has been computed by a computer simulation technique. This result and an incidental result for the relative free energy of hydration of the anions are in excellent agreement with experimental data. The simulation approach to ligand-receptor interactions that is described here has significant potential as a predictive tool in chemistry, biochemistry, and pharmacology.     

A worldwide survey of the use of simulation in anesthesia

PURPOSE: To gather information regarding the global use of simulation technology in education, evaluation and research in anesthesia. METHODS: The WorldWide Web was searched and located sites with simulation centres (n = 158) were mailed a 67-item questionnaire requesting information regarding demographics, personnel, education use and research involvement. Comments were solicited. Medical school data only are reported in this article. RESULTS: Two web sites were used to generate the list of simulation centres. Sixty responses were received (38%), with 41 emanating from medical schools. Seventy-seven percent of centres were involved in undergraduate education and 85% in postgraduate education. Few centres were involved in evaluation and/or competency assessments. Sixty-one percent of centres indicated ongoing research with a further 25% interested in international collaboration. University or university departmental-based funding largely supported simulation technology used in medical schools. The lack of financial and human resources was the single most common problem identified by respondents. CONCLUSIONS: From the survey responses received, opportunities for the simulator to be used for the assessment of performance appear to be under-utilized. This may be due to the lack of research in this area, lack of standardized, valid and reliable tests and the fact that most centres have only recently acquired this technology. Further research supporting the use of the simulator in education and evaluation is required.     

Topography of median eminence somatostatinergic innervation

Somatostatin (SRIF) in the central nervous system is mostly concentrated in the median eminence (ME). Immunocytochemical methods have revealed high densities of SRIF-positive perikarya between the preoptic area and the periventricular nucleus of the hypothalamus (NPE). The aim of the present study was to define more precisely the specific pathways of SRIF neurons from NPE to the ME. SRIF levels were measured by radioimmunoassay, following various hypothalamic transections. Frontal periventricular sections decreased SRIF-ME content by 70% (P less than 0.01), when located at the anterior end of the ME but no diminution was observed when the cuts were located anteriorly or posteriorly. Parasaggital transections decreased SRIF-ME levels by 50% (P less than 0.05) when located at the outer border of the ventromedial and premammillary nucleus, but the decrease was not significant when cuts were located anteriorly. Taken together, our data indicate that most SRIF-containing neurons, originating in the NPE, do not reach the ME directly along the border of the 3rd ventricle; instead they form a loop across the medial forebrain bundle before re-entering the mediobasal hypothalamus at the ME level.