Comparison and contrast of affinity chromatographic determinations of plasma glycated albumin and total glycated plasma protein

Aptasensor based optical detection of glycated albumin for diabetes mellitus diagnosis

Glycated albumin (GA) has been reported as an important biomarker for diabetes mellitus. This study investigates an optical sensor comprised of deoxyribonucleic acid (DNA) aptamer, semiconductor quantum dot and gold (Au) nanoparticle for the detection of GA. The system functions as a 'turn on' sensor because an increase in photoluminescence intensity is observed upon the addition of GA to the sensor. This is possibly because of the structure of the DNA aptamer, which folds to form a large hairpin loop before the addition of the analyte and is assumed to open up after the addition of target to the sensor in order to bind to GA. This pushes the quantum dot and the Au nanoparticle away causing an increase in photoluminescence. A linear increase in photoluminescence intensity and quenching efficiency of the sensor is observed as the GA concentration is varied between 0-14 500 nM. Time based photoluminescence studies with the sensor show the decrease in binding rate of the aptamer to the target within a specific time period. The sensor was found to have a higher selectivity towards GA than other control proteins. Further investigation of this simple sensor with greater number of clinical samples can open up avenues for an efficient diagnosis and monitoring of diabetes mellitus when used in conjunction with the traditional method of glucose level monitoring.

Determination of furosine in biomedical samples employing an improved hydrolysis and high-performance liquid chromatographic technique

Traditionally, the most sensitive and specific determination of non-enzymatic protein glycation has involved an 18-24-h acid hydrolysis in order to generate the compound furosine, which has been detected employing reversed-phase h.p.l.c. In this study, we have reported that significant quantities of furosine can be generated with much shorter hydrolysis times employing a 90-min vapor-phase acid hydrolysis procedure. The furosine generated by vapor-phase hydrolysis is then quantitated by pulsed amperometric detection using anion-exchange high-performance liquid chromatography. Employing this method, we were able to show that furosine generated from acid hydrolysis of purified hepatic membranes in a diabetic and non-diabetic animal model agreed with traditional methods assessing total glycated protein (i.e., boronate affinity methods).

High-performance liquid affinity chromatography and in situ fluorescent labeling on thin-layer chromatography of glycosphingolipids

A method combining high-performance liquid affinity chromatography and in situ fluorescent labeling on thin-layer chromatography is introduced for determination of glycosphingolipids. Glycolipids in crude extract from rat liver were separated quantitatively from neutral lipids and phospholipids with a phenylboronic acid-derivatized silica gel column. Glycolipids were eluted quantitatively with approximately 98% of crude extract recovered. This column is useful for selective cleanup of glycosphingolipids in crude extract from tissue. Simultaneously, a fluorometric determination of glycosphingolipids with 7-amino-4-methylcoumarin after NaIO4 oxidation on a TLC plate was introduced and its condition was optimized. Glycolipids in amounts ranging from 1 to 100 pmol are easily detectable and give linear responses over the respective ranges. The method is fast and useful for the determination of glycolipids from small amounts of biological samples and requires a minimum amount of about 1 mg of biological specimen for determination of glycolipids.

Glycosylated chicken growth hormone

In an attempt to raise monoclonal antibodies to chicken pituitary glycoprotein hormones, mice were immunized with the concanavalin A-adsorbed components of a hypophyseal extract. Fusions of these spleen cells with myeloma cells repeatedly yielded hybridoma lines secreting antibodies that recognized specifically the pituitary caudal acidophils, known as the somatotropes. This paper reveals the existence of a glycosylated counterpart of the well-established holoprotein form of chicken growth hormone, similar to what has been established for human growth hormone and prolactin.

Measurement of glycated albumin in diabetic patients by biospecific affinity chromatography

The percentage of glycated plasma albumin was measured by a procedure involving ammonium sulphate precipitation and Affi-Gel-Blue and phenylboronate chromatographies. The value correlates well with the amount of ketoamine-bound sugars determined by colorimetric assay (r = 0.98, n = 39). The normal mean value is 3.9 +/- 0.3% (mean +/- S.D., coefficient of variation = 7.7%, n = 32) and varies from 3.9 to 21% in diabetics (n = 54). A good correlation is found with the mean blood glucose value of the preceding twenty days (r = 0.92, n = 57). Because of its relative ease of determination, glycated albumin constitutes a good short-term glycemic index and an alternative to glycated haemoglobin in some specific cases.