The Environmental Context of Patient Safety and Medical Errors

The environmental context of patient safety and medical errors was explored with specific interest in rural settings. Special attention was paid to unique features of rural: healthcare organizations and their environment that relate to the patient safety issue and medical errors (including the distribution of patients, types of adverse events associated with learning, information flows, triage and transfer decisions, and culture of safety). Relevant organizational theories and strategies fo medical error reduction and prevention in rural health care settings were identified. Financial and technical assistance are needed to support the systematic collection of data from rural hospitals and other entities and to enhance relevant patient safety practices for rural America.     

Quantitative magnetization transfer imaging via selective inversion recovery with short repetition times.

Quantitative magnetization transfer imaging (qMTI) methods are able to estimate fundamental sample parameters, such as the relative size of the solid-like macromolecular proton pool and the spin exchange rate between this pool and the directly measured free water protons. One such method is selective inversion recovery (SIR), in which the free water protons are selectively inverted and the signal is fit to a biexponential function of the inversion time (TI). SIR uses only low-power pulses and requires no separate RF (B1) or static field (B0) field maps, and the analysis is largely independent of the macromolecular pool lineshape. These are all advantages over steady-state off-resonance saturation qMTI methods. However, up to now, SIR has been implemented only with repetition times TR>T1. This paper describes a modification of SIR with smaller TR values and a greater signal-to-noise ratio (SNR) efficiency.     

Multiple Implants for First Molar Prosthodontics

Problems that can occur when single implants are utilized to restore first molar teeth include the frequent loosening of screws, as well as screws and/or implant breakage. These may result from torquing and rotational movements of the prosthesis during masticatory and parafunctional mandibular movements. When sufficient bone and mesio-distal restorative space is present, the placement of two implants should be considered.     

Campath-1M--prophylactic use after kidney transplantation. A randomized controlled clinical trial

Campath-1M is a rat monoclonal IgM antibody that binds human complement and recognizes virtually all peripheral human mononuclear cells. It is known to be effective in T cell depletion of bone marrow grafts, and encouraging results were obtained in a pilot study in which the antibody was used in prevention and treatment of rejection of kidney, pancreas, and liver allografts. In this randomized controlled clinical trial, Campath-1M has been evaluated as a prophylactic agent following renal allografting. It is shown that patients who received a 10-day course of the antibody immediately postoperatively, in addition to standard therapy with high-dose cyclosporine (17 mg/kg), experienced a significantly lower incidence of early acute cellular rejection than control patients who received cyclosporine alone. There was no evidence of "rebound" rejection following the end of antibody treatment to suggest that rejection had merely been delayed. However, patients who received this additional immunosuppression experienced a significantly higher incidence of serious infections than controls, this negating any benefit from the treatment in terms of graft survival. Thus, a monoclonal antibody of broad specificity directed against lymphocytes may be effective as a prophylactic agent after organ transplantation but its use should be accompanied by a reduction in other immunosuppressive drugs.     

Trisomy of the short arm of chromosome 8: Association with translocation between chromosomes 8 and 22 46,XY,22−,t(8p22q)+

The case of a retarded child with trisomy of the short arm of chromosome 8 associated with translocation between the short arm of chromosome 8 and the long arm of chromosome 22 is reported. Balanced translocation involving the same chromosomes was present in the mother and brother of the propositus. The specific chromosomes involved in the abnormality in this family were identified by use of fluorescence microscopy with quinacrine mustard staining, autoradiography and Giemsa banding. This appears to be the first case report of this anomaly, although trisomy of the short arm of chromosome 9 has been reported previously.     

A model for susceptibility artefacts from respiration in functional echo-planar magnetic resonance imaging

Respiration causes variations in the signals acquired during magnetic resonance imaging (MRI) and therefore is a significant source of noise in functional brain imaging. A primary component of respiratory noise may arise from variations of bulk susceptibility or air volume in the chest. Here we investigate the nature of the image artefacts that can be caused by such changes. We develop a simple model which attempts to mimic the effects of variations in susceptibility and volume during respiration. Theoretical calculations, computer simulations and imaging experiments with this model show that small variations in susceptibility within the thorax from alterations in the paramagnetism of cavity gas may lead to a shift of the image on the order of 0.1 pixels as well as a shading of the intensity by +/-1%. These effects are observed to be predominant in the phase-encoding direction. They may lead to the production of spurious activations in functional MRI and are likely to be of more importance at higher field strengths.     

Application of influence diagrams to prostate intensity-modulated radiation therapy plan selection

The purpose is to incorporate clinically relevant factors such as patient-specific and dosimetric information as well as data from clinical trials in the decision-making process for the selection of prostate intensity-modulated radiation therapy (IMRT) plans. The approach is to incorporate the decision theoretic concept of an influence diagram into the solution of the multiobjective optimization inverse planning problem. A set of candidate IMRT plans was obtained by varying the importance factors for the planning target volume (PTV) and the organ-at-risk (OAR) in combination with simulated annealing to explore a large part of the solution space. The Pareto set for the PTV and OAR was analysed to demonstrate how the selection of the weighting factors influenced which part of the solution space was explored. An influence diagram based on a Bayesian network with 18 nodes was designed to model the decision process for plan selection. The model possessed nodes for clinical laboratory results, tumour grading, staging information, patient-specific information, dosimetric information, complications and survival statistics from clinical studies. A utility node was utilized for the decision-making process. The influence diagram successfully ranked the plans based on the available information. Sensitivity analyses were used to judge the reasonableness of the diagram and the results. In conclusion, influence diagrams lend themselves well to modelling the decision processes for IMRT plan selection. They provide an excellent means to incorporate the probabilistic nature of data and beliefs into one model. They also provide a means for introducing evidence-based medicine, in the form of results of clinical trials, into the decision-making process.