Magnetic resonance of the encephalon in 17 patients with ocular Beh?et''s disease

OBJECTIVE: To evaluate the relationships between patient and physician pretreatment expectations of pain relief and subsequent pain relief reported by chronic pain patients immediately after treatment. DESIGN: Prospective study of consecutive patients undergoing a procedure in a pain clinic for treatment of chronic pain. Patients rated their current pain level and their expectation of pain relief immediately prior to undergoing a procedure (e.g., intravenous drug infusion, nerve block) for the treatment of chronic pain. Simultaneously and independently, the treating physician completed a similar questionnaire. At completion of the procedure, patients rated their current pain level and degree of pain relief. SETTING: University of Washington Multidisciplinary Pain Center procedure suite. PATIENTS: Forty-six consecutive chronic pain patients. INTERVENTION: Intravenous drug infusions and nerve blocks. OUTCOME MEASURES: Current pain and pain relief ratings. RESULTS: Patients' pain relief expectation ratings were not correlated significantly with their postprocedure pain relief ratings or pre-post procedure changes in pain ratings. However, a statistically significant correlation was found between physician expectations of pain relief and patient pain relief ratings and patient pre-post procedure changes in pain. CONCLUSIONS: The results of this study suggest that physicians are better predictors than are patients of patients responses to these procedures and/or that physicians may somehow subtly communicate their expectations to patients during the procedure, and these expectations then influence patient response. Patient pretreatment expectations may not always play a significant role in nonspecific treatment effects.     

Ventricular arrhythmias in myocardial hypertrophy of various origins

BACKGROUND: Elevated serum sialic acids are associated with increased cardiovascular mortality, but sialic acid levels have not been studied in cardiac tissue. METHODS: Myocardial samples were obtained at the time of transplantation from 23 patients (age 54 +/- 12 years) with heart failure secondary to ischemic heart disease and 16 patients (age 51 +/- 7 years) with idiopathic dilated cardiomyopathy (DCM). A control group comprised postmortem samples obtained from 14 patients (age 70 +/- 5 years) who died of non-cardiovascular causes. Ventricular sialylation was quantitated using the sialic acid-specific lectins Maackia amurensis agglutinin (MAA) and Sambucus nigra agglutinin (SNA) using a chemiluminescence assay. Results are expressed as the percentage (+/-standard error of the mean) of the binding of lectin to a standardized control sample of human myocardium. RESULTS: Ventricular sialylation recognized by MAA was 55 +/- 7% in patients with heart failure secondary to ischemic heart disease compared with 26 +/- 7% for DCM (p = 0.006) and 32 +/- 8% for controls (p = 0.04), and that recognized by SNA was 69 +/- 7% in patients with heart failure secondary to ischemic heart disease compared with 42 +/- 6% for DCM (p = 0.006) and 38 +/- 7% for controls (p = 0.006). No significant difference in ventricular sialylation was observed between patients with DCM and controls. CONCLUSION: Myocardial levels of sialic acids are significantly increased in patients with heart failure secondary to ischemic heart disease compared with patients with idiopathic dilated cardiomyopathy and controls. Our findings are important in view of recent reports of an association between serum sialic acid concentration and cardiovascular mortality and require further investigation.     

Chronic pain in elderly people

Using the fear-potentiated startle paradigm in rats, 4 experiments examined whether the inhibitory effect of a feature is evident after its offset following serial feature-negative discrimination training (A+ and X-->A-). When startle probes were presented shortly after the offset of X on X-->A test trials, the inhibitory properties of X were observed immediately after its offset. Furthermore, trace reinforcement of X (X-->+), but not delay reinforcement (X+), disrupted the ability of X to inhibit fear-potentiated startle on X-->A trials. Trace conditioning to X was also retarded after A+ and X-->A- training. These results suggest that the inhibitory properties of the serially trained feature are present after its offset and raise the possibility that either temporal information regarding nonreinforcement or poststimulus attributes of X acquire inhibitory properties.     

Certain nonlinear partially observable stochastic optimal controlproblems with explicit control laws equivalent to LEQG/LQG problems

This paper is concerned with partially observed stochastic optimal control problems when nonlinearities enter the dynamics of the unobservable state and the observations as gradients of potential functions. Explicit representations for the information state are derived in terms of a finite number of sufficient statistics. Consequently, the partially observed problem is recast as one of complete information with a new state generated by a modified version of the Kalman filter. When the terminal cost is quadratic in the unobservable state and includes the integral of the nonlinearities, the optimal control laws are explicitly computed, similar to linear-exponential-quadratic-Gaussian (LEQG) and linear-quadratic-Gaussian (LQG) tracking problems. The results are applicable to filtering and control of Hamiltonian systems     

Estimating the viewing parameters of random, noisy projections ofasymmetric objects for tomographic reconstruction

The ability to determine the viewing parameters of objects from their projections has enabled well established tomographic techniques to be employed in the 3D reconstruction of objects from images obtained via modalities where the orientation of the objects cannot be controlled. A method is described for the determination of the viewing parameters of randomly acquired projections of asymmetric objects. It extends upon the common lines algorithm by determining the relative orientation of projections from the location of lines of intersection among the Fourier transforms of the projections in 3D Fourier space. A new technique for finding the lines of intersection in the presence of translational displacement, and for subsequently finding the translational displacement, is presented. The complete algorithm is described and its efficacy is demonstrated using real data. A new technique for dealing with noise is also discussed     

On a large-gain theorem

The aim of this paper is to give a general quantitative requirement which the loop gain must satisfy in order to stabilize a given unstable (possibly nonlinear and time-varying) plant, namely that the gain must exceed one.     

Estimation of deformation gradient and strain from cine-PC velocity data

Phase contrast magnetic resonance imaging (MRI) can provide in vivo myocardial velocity field measurements. These data allow densely spaced material points to be tracked throughout the whole heart cycle using, for example, the Fourier tracking algorithm. To process the tracking results for myocardial deformation and strain quantification, we developed a method that is based on fitting the tracking results to an appropriate local deformation model. We further analyzed the accuracy and precision of the method and provided performance predictions for several local models. In order to validate the method and the theoretical performance analysis, we conducted controlled computer simulations and a phantom study. The results agreed well with expectations. Human heart data were also acquired and analyzed, and provided encouraging results. At the signal-to-noise ratio (SNR) level and spatial resolution expected in clinical settings, the study predicts strain quantification accuracy and precision that may allow the technique to become a practical and powerful noninvasive approach for the study of cardiac function, although clinically acceptable data acquisition strategies for three-dimensional (3-D) data are still a challenge.