A Simpler Creatinine Index Can Predict Long-Term Survival in Chinese Hemodialysis Patients.

BACKGROUND: Low lean body mass (LBM) is an indicator of malnutrition inflammation syndrome, which is common in hemodialysis (HD) patients. The creatinine index (CI) has been validated as a reliable method to estimate LBM and evaluate the protein-energy status of HD patients. However, the traditional creatinine index formula was complex. We sought to investigate the impact of CI derived from a new simple formula on Chinese HD patient outcomes. METHODS: In this retrospective cohort study, we enrolled 1269 patients who initiated HD between February 1981 and February 2012 and followed them until the end of February 2013. CI was calculated using the simple creatinine kinetic model (CKM) formula. Multiple linear regression analysis and Cox regression proportional hazard analysis were used to define independent variables and compare survival between groups. RESULTS: The 1269 HD patients were categorized into 3 groups according to the tertiles of calculated CI between men and women. Each group consisted of 423 patients (50.6% men, 49.4% women). Patients in the highest sex-specific tertile of CI had longer overall survival (HR, 0.46; P 0.002). BMI did not significantly associate with survival after adjustment (HR,0.99; P 0.613). CONCLUSIONS: CI derived from the simple CKM formula serves as a good parameter than BMI to predict the survival of HD patients. The formula could extend its convenient use in clinical practice for HD patients.

Design and experimental evaluation of a 256-channel dual-frequency ultrasound phased-array system for transcranial blood-brain barrier opening and brain drug delivery.

Focused ultrasound (FUS) in the presence of microbubbles can bring about transcranial and local opening of the blood-brain barrier (BBB) for potential noninvasive delivery of drugs to the brain. A phased-array ultrasound system is essential for FUS-BBB opening to enable electronic steering and correction of the focal beam which is distorted by cranial bone. Here, we demonstrate our prototype design of a 256-channel ultrasound phased-array system for large-region transcranial BBB opening in the brains of large animals. One of the unique features of this system is the capability of generating concurrent dual-frequency ultrasound signals from the driving system for potential enhancement of BBB opening. A wide range of signal frequencies can be generated (frequency = 0.2-1.2 MHz) with controllable driving burst patterns. Precise output power can be controlled for individual channels via 8-bit duty-cycle control of transistor-transistor logic signals and the 8-bit microcontroller-controlled buck converter power supply output voltage. The prototype system was found to be in compliance with the electromagnetic compatibility standard. Moreover, large animal experiments confirmed the phase switching effectiveness of this system, and induction of either a precise spot or large region of BBB opening through fast focal-beam switching. We also demonstrated the capability of dual-frequency exposure to potentially enhance the BBB-opening effect. This study contributes to the design of ultrasound phased arrays for future clinical applications, and provides a new direction toward optimizing FUS brain drug delivery.