Computed tomography of acute radiation nephritis

A patient with Hodgkin’s disease received a fractionated 3, 740 rad dosage over 4 weeks to a portal that included both kidneys. Three months later a computed tomographic scan obtained 2 hours after intravenous contrast injection demonstrated sharply demarcated, dense, persistent nephrograms corresponding to the irradiated areas. These changes are ascribed to acute radiation nephritis, reflecting tubular stasis and ischemia.     

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.     

Influence of mesh materials on collagen deposition in a rat model.

Alterations of the extracellular matrix (ECM) with its major component collagen are increasingly discussed as possible risk factors implicated in the development of abdominal-wall herniation. Because of the widespread use of alloplastic meshes for the surgical repair of hernias, an animal study was performed to analyze the influence of various mesh materials on the quantity and quality of collagen deposition. In 60 male Sprague-Dawley rats an abdominal replacement was performed using three different kinds of mesh materials: polyester (PE), a pure polypropylene (PP), and a composite mesh made of polypropylene and polyglactin (PG). A simple fascia suture repair served as control. The count of fibroblasts, the collagen/protein ratio, the type I/III collagen ratio, and the expression of basic fibroblast growth factor (b-FGF) at the interface were analyzed after 7, 21, and 90 days. The ratio of collagen to overall protein (microg/mg) showed significant differences comparing different mesh materials (sham controls 38.44 +/- 16.33 microg/mg, PE 68.5 +/- 23.8 microg/mg, PP 101.6 +/- 32.3 microg/mg, PG 49.6 +/- 11.6 microg/mg at day 90). The ratio of collagen type I/III increased over time in all groups. However, 90 days after mesh implantation the ratio was always significantly lowered compared to the controls. No significant difference was found comparing different mesh materials. The alteration of the scar composition is closely connected to an increased b-FGF expression. b-FGF and count of fibroblasts highly correlated (r =.95) and showed significant elevated levels compared to simple suture repair. The results of our study strongly support the notion that wound healing is affected by mesh implantation. The quality of the ECM deposition as determined by collagen type I/III ratio is impaired in general, whereas the quantity of ECM deposition is markedly influenced by the kind of mesh material.     

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.