Development of a membrane-less dynamic field gradient focusing device for the separation of low-molecular-weight molecules.
Microfluidic preparative free-flow isoelectric focusing in a triangular channel: system development and characterization.
Comparative effects of six intraocular vital dyes on retinal pigment epithelial cells.
Fiducial markers for combined 3-dimensional mass spectrometric and optical tissue imaging.
Pathways of infusate loss during convection-enhanced delivery into the putamen nucleus.
Simple spectrophotometric determination of urinary albumin by dye-binding with use of bromphenol blue.
(22/29)This procedure for routine quantification of albumin in urine is based on the dye-binding properties of albumin with bromphenol blue. The absorbance of 100 microL of urine mixed with 3 mL of color reagent is measured against blank reagent at 610 nm after 30 s. Results vary linearly with albumin concentration up to 6 g/L. The reaction is pH independent in the physiological range. It is not subject to substantial interference by uric acid, creatinine, calcium, sodium chloride, or bilirubin. The presence of globulins produces a small positive error. Within-run precision (CV) was 4.8, 1.5, and 0.9%, and day-to-day precision was 11.2, 2.0, and 1.9%, for samples containing albumin at about 0.1, 1.0, and 6.0 g/L, respectively. Results by a radial-immunodiffusion method (x) correlated well with those by the proposed method (y): r = 0.986; y = 0.98x + 0.096; n = 64. The method can also be used to detect globulins, such as Bence Jones protein, by measuring the ratio of the absorbance at 30 min to that at 30 s. (+info)
Ektachem multilayer dry-film assay for ammonia evaluated.
(23/29)We evaluated the Kodak Ektachem multilayer dry-film method for ammonia. Within-day precision (CV) was 5.9% and 2.7% at ammonia concentrations of 53 and 654 mumol/L, respectively. Between-run precision (CV) was 7.8% and 7.3% at 51 and 109 mumol/L, respectively. Correlation with a manual ion-exchange chromatography-Berthelot reaction-based method (x) was good (y = 0.96x - 1.37; r = 0.984; SEE = 9.16). The response of the method varies linearly with ammonia concentration up to 900 mumol/L. Bilirubin less than or equal to 270 mg/L, triglycerides less than or equal to 6.0 g/L, and slight hemolysis did not interfere. The concentration of ammonia in plasma of 120 healthy adults was 16-53 mumol/L (nonparametric central 95 percentiles). (+info)
Kinetic assay of human pepsin with albumin-bromphenol blue as substrate.
(24/29)A novel substrate, albumin complexed with bromphenol blue, has been developed for the assay of human gastric juice pepsin by a kinetic method in the Cobas centrifugal analyzer. The action of pepsin on the complex degrades the albumin and releases the dye. The change in the color of the substrate is a zero-order reaction. Human and porcine pepsin have different Km's with the new substrate. This kinetic method has a throughput of 28 tests in approximately 10 min and good precision (CV = 2.0%). Other advantages are analysis in homogeneous solution (thereby eliminating the need to separate substrate and products), lack of interference from bilirubin or phenol red, and the expression of pepsin activity in IUB enzyme units. (+info)