Lupus organ damage: what is damaged in Asian patients?

Assessment of organ damage has become the standard outcome measure for morbidity and mortality in patients with lupus. Ethnicity is thought to be a marker for genetic, environmental, behavioral, and other variables that may affect disease outcomes. Previous studies suggest that Asians residing in western countries had significantly higher prevalence of damage compared with Whites. In contrast, studies performed in Chinese, Korean and Arab patients showed that the overall prevalence of damage and the most commonly involved organs (neuropsychiatric and musculoskeletal) were similar to Whites. Compared with their Asian counterparts, Pakistani and Jewish patients appeared to have a higher prevalence of damage, most likely secondary to longer disease duration. Chinese patients had an increased prevalence of premature gonadal failure, whereas patients residing in western and southern Asia had more skin damage. When compared with Whites, Asian patients had more renal damage but less ocular and cardiovascular damage. Risk factors associated with organ damage in Asian lupus patients included older age, higher disease activity, and the use of cyclophosphamide and steroids. Further investigations into other determinants such as genetic predisposition, socioeconomic factors, prevalence and severity of disease manifestations, and treatment, is needed in order to understand the variation in damage accrual in lupus patients from different ethnicities.

Quantitative spectral/spatial analysis of phased array coil in magnetic resonance imaging based on method of moment.

A new approach for analysis of RF coils in magnetic resonance (MR) experiments is reported. Instead of assuming current distribution in conventional quasi-static algorithm, this approach transforms the coil geometry into an equivalent circuit for complex current calculation. Self and mutual inductance are taken into consideration. Frequency responses of RF coils and transverse magnetic field (B1) maps can be simulated. This approach is especially efficient for phased array coil design for its small matrix size when implemented on computers. Experiments on both single surface coil and phased array coils are consistent with simulation results. Index Terms-Magnetic resonance, method of moment, phased array coil, RF coil.

High-resolution MR imaging of water diffusion in the rabbit lens.

Movement of water in the lens, specifically water diffusion, was examined with diffusion imaging and H217O-enhanced proton imaging. Diffusion imaging showed restricted water self-diffusion in the cortex which was not concurrent with the change in proton density; nevertheless it was dependent on the gradient direction and might be related to lens fiber/protein organization. The difference in water diffusion patterns between control and galactosemic cataract was subtle but distinguishable. On the other hand, intracameral H217O injection allowed visualization of water movement across the lens. In galactosemic cataracts, water diffused from the anterior cortex towards posterior cortex and into the vitreous. This pattern was not seen in the normal lens.

Measurement of water movement in the rabbit eye in vivo using H2(17)O.

Topically applied (eyedrop) H2(17)O (10% enrichment) was used in magnetic resonance studies to quantify intraocular water dispersion in vivo. The rate of H2(17)O removed from the aqueous chamber is in the order of 0.1 ml/min/ml of tissue. Similar results are obtained with either proton imaging or 17O spectroscopy. Parallel experiments of direct injection of H2(17)O into the aqueous chamber supported the topical data. Proton MR imaging of H2(17)O dissipation from the aqueous chamber with clinical imagers, coupled with eyedrop application, suggests clinical possibilities.