Interpreting cerebrospinal fluid pleocytosis in HIV in the era of potent antiretroviral therapy

Background  

Cerebrospinal fluid (CSF) pleocytosis may be seen in asymptomatic HIV-infected individuals. This finding complicates interpretation of CSF abnormalities when such individuals are evaluated for other central nervous system infections. The goal of this study was to determine the relationship between CSF pleocytosis, central nervous system (CNS) antiretroviral penetration, adherence to antiretroviral medication regimens, neurological symptoms and performance on neuropsychological tests.     

System for prostate brachytherapy and biopsy in a standard 1.5 T MRI scanner.

A technique for transperineal high-dose-rate (HDR) prostate brachytherapy and needle biopsy in a standard 1.5 T MRI scanner is demonstrated. In each of eight procedures (in four patients with intermediate to high risk localized prostate cancer), four MRI-guided transperineal prostate biopsies were obtained followed by placement of 14-15 hollow transperineal catheters for HDR brachytherapy. Mean needle-placement accuracy was 2.1 mm, 95% of needle-placement errors were less than 4.0 mm, and the maximum needle-placement error was 4.4 mm. In addition to guiding the placement of biopsy needles and brachytherapy catheters, MR images were also used for brachytherapy treatment planning and optimization. Because 1.5 T MR images are directly acquired during the interventional procedure, dependence on deformable registration is reduced and online image quality is maximized.     

User interface paradigms for patient-specific surgical planning: lessons learned over a decade of research.

This paper covers work in virtual reality-based, patient-specific surgical planning over the past decade. It aims to comprehensively examine the user interface paradigms and system designs during that period of time and to objectively analyze their effectiveness for the task. The goal is to provide useful feedback on these interface and implementation paradigms to aid other researchers in this field. First, specialized systems for specific clinical use were produced with a limited set of visualization tools. Later, through collaboration with NASA, an immersive virtual environment was created to produce high-fidelity images for surgical simulation, but it underestimated the importance of collaboration. The next system, a networked, distributed virtual environment, provided immersion and collaboration, but the immersive paradigm was found to be of a disadvantage and the uniqueness of the framework unwieldy. A virtual model, workbench-style display was then created using a commercial package, but limitations of each were soon apparent. Finally, a specialized display, with an integrated visualization and simulation system is described and evaluated. Lessons learned include: surgical planning is an abstract process unlike surgical simulation; collaboration is important, as is stereo visualization; and that high-resolution preoperative images from standard viewpoints are desirable, but interaction is truly the key to planning.     

Conjunctival flaps in the treatment of refractory pseudomonas corneal abscess

Pseudomonas corneal abscess can result in a rapid downhill clinical course despite institution of appropriate medical measures. In this situation the clinician is faced with surgical intervention. A series of patients treated and stabilized through conjunctival flap therapy are presented. The role of conjunctival flap therapy in halting the progression of this entity is described.     

Preliminary observation of speech disorder in obstructive and mixed sleep apnea

Clinical observation suggested that speech disorder seemed to be associated with sleep apnea. We recorded a standard speech sample from 39 matched subjects in three groups, 13 sleep apnea individuals, 13 subjects with COPD, and 13 subjects without sleep apnea or COPD. Three speech pathologists in a single blind listening task of the recorded samples judged whether or not speech disorder was present. Eight of the sleep apnea subjects were judged to have disordered speech compared to three of the COPD group and one of the non-sleep apnea, non-COPD (normal) group. These results were statistically significant. This supports a clinical impression that speech disorder is more common in sleep apnea than expected. There may be common anatomic and physiologic disturbances present between the two conditions, and perhaps disordered speech is a sign of sleep apnea.     

Short-term changes in tonic accommodation

Experiments were performed to determine the diurnal variation of, as well as the influence of total darkness on, tonic accommodation. In general, under both conditions trend analysis showed that variations in tonic accommodation over time were either nonsystematic in nature or could be best described by a simple linear function. Given the relatively small range of mean tonic accommodation values over time (0.5 to 1.1 D), the results demonstrate the robustness and stability of tonic accommodation under naturally occurring viewing conditions during the course of a day. In contrast, during the 2-hr period in total darkness, tonic accommodation exhibited a three-fold increase in mean range (0.6 to 2.5 D) as well as a significant increasing linear trend in some subjects, suggesting less stability of tonic accommodation in the absence of visual stimuli.