Plasma protein homeostasis in chronic hemodialysis patients

The concentrations of 25 plasma proteins were measured in 29 patients with chronic renal insufficiency. All the patients had terminal renal failure and were treated with intermittent hemodialysis, but were otherwise in good general condition at the time of investigation. The plasma levels of 8 proteins with Mr<50 kD were significantly elevated compared to normal subjects. In contrast, only 2/17 proteins of greater size were found in increased concentrations. The degree of increase in concentration differed substantially between individual low molecular weight proteins, suggesting a complex metabolism in addition to delayed renal elimination. Acute phase proteins and immunoglobulins were not affected by renal insufficiency per se, although erythrocyte sedimentation rates were generally high. The synthesis of acute phase proteins increased normally during the course of inflammation. We conclude that although the sedimentation rate is of no value, complicating inflammatory processes can be traced by quantitative analysis of acute phase proteins, including C-reactive protein, even in patients with severe chronic renal insufficiency

Intracavity interrogation of an array of fiber Bragg gratings

In this work, we explore the interrogation of an array of fiber Bragg gratings as part of a laser cavity. A semiconductor optical amplifier in a sigma-shaped fiber cavity provides gain and is gated periodically at a rate that matches the roundtrip time associated with each grating of the array. The interrogator exhibits clear laser properties such as a threshold and linewidth narrowing. Besides improving the signal-to-noise ratio and enabling the re-use of wavelengths, it is found that this interrogation scheme enables monitoring of weak gratings spaced by less than 1 cm. Intracavity grating interrogation studied here is found to be a simple and powerful way to increase the number of sensor points for industrial applications.QC 20201224</p

Robotic implementation of a microchip-based protein clean-up and enrichment system for MALDI-TOF MS readout

A capillary filling microfluidic proteomic sample processing system has been realized in an automated set-up. Chip-integrated solid-phase extraction is performed in a 96-array format followed by sequential capillary action elution into a piezoelectric microdispenser and subsequent transfer to MALDI targets. Samples are eluted and deposited in volumes of 200–300 nl. The robotic system offers calibration to user-defined microextraction arrays and MALDI-target formats at micrometre resolution. Built-in force feedback control ensures a precise and robust microchip docking/handling in three dimensions. An efficient automated washing protocol eliminates analyte carry-over. System throughput ranges typically from 50–100 samples h-1