Paraoxonase 1 arylesterase activity and mass are reduced and inversely related to C-reactive protein in patients on either standard or home nocturnal hemodialysis.

UNLABELLED: Human serum paraoxonase (PON1) activity is reduced in standard hemodialysis (SHD) (4 hours, 3 days/week) patients. Home nocturnal hemodialysis (HNHD) (8 hours, 6 days/week), provides a greater dialysis dose resulting in a greater clearance of metabolites. Whether improvements in the metabolic milieu of HNHD patients results in different PON1 activity levels compared to SHD patients is unclear. We determined serum PON1 mass and arylesterase activities in a group of HNHD patients and compared them to SHD patients and a group of healthy controls (HC). PATIENTS AND METHODS: We measured PON1 arylesterase activity and mass, C-reactive protein (CRP), cystatin C, total and high-density lipoprotein (HDL) cholesterol, triglycerides, apolipoproteins A-I and B in 15 HNHD, 15 SHD and 15 HC participants. RESULTS: PON1 arylesterase activity (p < 0.001) and mass (p < 0.05) were significantly higher in HC participants compared to SHD and HNHD participants, although no significant differences were noted between HD groups. CRP (p < 0.05) was significantly higher in SHD compared to HC participants and there were no significant differences noted between HD groups. Cystatin C (p < 0.001) was significantly different among the 3 groups. There were no significant differences noted in any lipoprotein parameters among the groups. PON1 activity (r = -0.636, p < 0.001) and mass (r = -0.425, p = 0.019) were inversely correlated with CRP in HD patients. CONCLUSION: PON1 is reduced in HNHD patients compared to HC subjects, independent of the concentration of HDL cholesterol. Within subjects on HD, the combination of increased CRP and reduced PON1 may identify subjects at a high risk for cardiovascular complications.

Multimode laser emission from dye doped polymer optical fiber.

Multimode laser emission is observed in a polymer optical fiber doped with a mixture of Rhodamine 6G (Rh 6G) and Rhodamine B (Rh B) dyes. Tuning of laser emission is achieved by using the mixture of dyes due to the energy transfer occurring from donor molecule (Rh 6G) to acceptor molecule (Rh B). The dye doped poly(methyl methacrylate)-based polymer optical fiber is pumped axially at one end of the fiber using a 532 nm pulsed laser beam from a Nd:YAG laser and the fluorescence emission is collected from the other end. At low pump energy levels, fluorescence emission is observed. When the energy is increased beyond a threshold value, laser emission occurs with a multimode structure. The optical feedback for the gain medium is provided by the cylindrical surface of the optical fiber, which acts as a cavity. This fact is confirmed by the mode spacing dependence on the diameter of the fiber.