Glycated hemoglobin in hypoglycemia.

The effect of hypoglycemia--caused by hyperinsulinism in insulinoma patients and in diabetic patients with frequent episodes of hypoglycemia--on glycated hemoglobin was studied. The amount of sugar bound to total hemoglobin in hypoglycemia samples was found to be significantly lower than in those which were normal or hyperglycemic. The amount of total HbA1 fraction, as determined by the mini-column method, was significantly higher than expected on the basis of the corresponding values for total glycated hemoglobin. Evidence is presented to show that this is due to the formation of a hitherto unrecognized HbA1 constituent(s) denoted here as HbA1x.

A spectrophotometric method for simultaneous determination of protein-bound hexoses and fucose with a mixture of L-cysteine and phenol.

A very suitable spectrophotometric method for simultaneous determination of protein-bound hexoses and fucose is presented. A mixture of L-cysteine and phenol in sulfuric acid was used as reagent, whereas absorption measurements were carried out at two wavelengths, namely at 398 nm for fucose and 490 nm for hexoses determination. Optimum conditions for the application of the method were established, special attention being paid to the possible interference of fucose determination with that of hexoses, and vice versa. The proposed method was applied to the determination of hexoses and fucose in serum glycoproteins and seromucoids. The method was found to be very practical enabling a simultaneous determination of both kinds of carbohydrates; moreover, it was proved to be more sensitive and specific in comparison with methods commonly used for individual determination of fucose with L-cysteine and hexoses with phenol.

Lithium ion influence on N-acetyl-beta-glucosaminidase isoenzymes serum level.

N-acetyl-beta-glucosaminidase (NAG) is a lysosomal enzyme found in most human cells, including those from the nervous system and kidneys. There are several different NAG forms in human tissues and fluids, but isoenzymes A and B are the most abundant, presenting about 98% of the whole NAG activity in normal serum. The paper is dealing with the total NAG serum level, main isoenzymes (A and B) activity, their ratio and possible lithium ion influence in affectively disordered patients. The sample consisted of thirteen bipolar-euthymic patients who had been receiving lithium for more than two years. The results pointed out reduction in total serum NAG activity, the lithium ion influence absence on total serum NAG activity, but at the same time the important modifying effects on isoenzyme NAG activities.