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PubMed1989

[Fructosamine and glycosylated hemoglobin as parameters of hyperglycemia].

We have determined the parameters fructosamine and A1 glycosylated hemoglobin, observing a good correlation between them. When analyzing both techniques, the determination of fructosamine proved to be more precise. Considering the significance of each of the tests, we conclude that these parameters cannot substitute for each other but are complementary and that the convenience of fructose determination can not invalidate the utility of determining the glycosylated hemoglobin.

Adolescent↗
PubMed1989

Effect of altered eating pattern on serum fructosamine: total protein ratio and plasma glucose level.

The effect of alteration of eating pattern during Ramadan on body mass index (BMI), serum fructosamine: total protein ratio (F/TP), and glucose level in 18 healthy male Asiatic Moslems were studied. The results showed a significant decrease (p less than 0.025) in F/TP at the second week of Ramadan in 11 subjects who experienced continuous decrease in BMI throughout Ramadan. The remaining 7 subjects showed no significant changes in BMI and F/TP. No evidence of hypoglycaemia was observed in the subjects during the study. Serum fructosamine: total protein ratio in subjects with altered eating pattern preferably should be interpreted along with the change in body mass index.

Adult↗
PubMed1988

The quality of performance of the fructosamine test.

The performance of fructosamine assays in 35 laboratories was assessed over a six month period in 1987. While agreement between laboratories was poor in the range expected in diabetic patients, most laboratories were internally consistent. The interlaboratory differences are largely attributed to the calibration methods used for this test. Fructosamine results from any one laboratory must not be interpreted by comparison with data from other laboratories or the literature. Other common biochemical tests were found to suffer from similar problems, but to a less serious extent.

Calibration↗
PubMed1988

Stability of serum fructosamine during storage.

Stability of serum fructosamine during storage was evaluated in serum specimens obtained from 27 diabetic individuals. The samples were divided into six aliquots, which were stored at -20 degrees C and -70 degrees C for two, eight, and 16 months. The minor systematic differences between the six treatments contrasted with the considerable variation of individual specimens. The mean percentage changes in the six treatments ranged between -4.6% and 7.5%, whereas the changes in individual specimens ranged from -20% to 26.7%. Several factors evidently contribute to this variation, one being progressive in vitro glycation, especially at -20 degrees C. Small changes in fructosamine concentrations between consecutively drawn specimens, determined after storage, evidently should be interpreted cautiously. Low temperatures, at least -70 degrees C, are preferable to minimize pre-analytical variation during storage.

Blood Glucose↗
PubMed1988

[Comparison of fructosamine and Hba1c for the evaluation of metabolic control of diabetic patients].

Fructosamine values, and the influence thereon of age, BMI and sex, were determined in 384 nondiabetic individuals aged between 20 and 95 years. In this control group mean F levels were 2.45 +/- 0.25 mmol/l and were age-related only, rising from 2.3 in the second decade to 2.6 in the eighth. We compared F and HbA1c in 135 diabetic patients. F correlated with HbA1c in the diabetic group (r = 0.76, p less than 0.001). Because of its biological properties fructosamine could become a useful pointer in the metabolic follow-up of diabetic patients, especially where clinic visits are frequent.

Adult↗
PubMed1988

Re-evaluation of the fructosamine reaction.

The difference in spectral characteristics between 1-deoxy-1-morpholinofructose (DMF) and protein/plasma samples in the fructosamine reaction has been related to the solubility of the diformazan formed by reduction of nitro blue tetrazolium chloride. Addition of the surfactant Triton X-100 (20 g/L) to the reagent buffer not only corrects this anomaly but also enhances the absolute response. Detailed investigation of DMF and dihydroxyacetone as calibration standards for the reaction established a clear preference for the latter. Fundamental differences in reaction kinetics were also noted between the Amadori rearrangement products of glucose formed from morpholine (DMF) or the amino lysine groups of protein (glycated albumin). From the reactivity of dihydroxyacetone, as well as glyceraldehyde, observed in the fructosamine reaction, and the presence of this class of compounds (trioses) in human plasma, we infer that they may also contribute to the differentiation of diabetic and non-diabetic samples.

Fructosamine↗
PubMed1987

[Determination of fructosamine on the Cobas-Bio centrifuge system. Importance of white reagent].

An automated assay for fructosamine on Cobas-Bio centrifugal analyzer with subtracting the contribution of the albumin matrix present in standards is described. This rapid and simple test has suitable analytical performances. Fructosamine concentrations were measured in 100 healthy subjects and in 95 diabetic patients. For the diabetic patients, results were compared with those obtained from a commercialized test kit.

Adult↗
PubMed1987

Inhibitory effect of superoxide dismutase on fructosamine assay.

The fructosamine assay measures the degree of nonenzymatic protein glycation by virtue of the reducing properties of such proteins in alkaline conditions. We report the marked inhibitory effect of superoxide dismutase (EC 1.15.1.1) on the reducing activity both of protein glycated in vitro and of diabetic sera, indicating superoxide intermediacy in the fructosamine reaction. The free-radical intermediates may be of analytical significance when pathological and physiological changes in serum anti-oxidant activity occur. They may also be of pathological significance in diabetic microangiopathy and protein browning.

Diabetes Mellitus↗
PubMed1995

The comparison of 50 grams glucose challenge test, HbA1c and fructosamine levels in diagnosis of gestational diabetes mellitus.

We evaluated the sensitivity, specificity, positive and negative predictive values of 50 grams glucose challenge test, serum fructosamine and HbA1c levels as screening tests for gestational diabetes mellitus. Forty-two pregnant patients between the 24th and 28th week of their pregnancies were included in the study. Blood fructosamine and HbA1c levels did not differ significantly from the 50 grams glucose challenge test and were concluded to be alternatives to this test. Any combination of these 3 tests gives better results than a single test, but no one of the combinations is superior to the others.

Blood Glucose↗
PubMed1993

Glucose, glycated hemoglobin and fructosamine levels in essential hypertension.

It has been shown that a significant correlation is present between blood pressure and plasma glucose concentrations among nondiabetic individuals. Blood glycated hemoglobin, serum glucose and fructosamine concentrations were determined in forty nonobese individuals, twenty with untreated essential hypertension and twenty with normal blood pressure. The results demonstrated a decrease in fasting serum glucose and blood glycated hemoglobin values in hypertensive group compared to the healthy controls. Although, a minor decrease is observed in hypertensive group, no significant alteration is detected in fructosamine values between these two groups.

Adult↗
PubMed1996

[Fructosamine in blood serum, binding and degradation of 125J-insulin by erythrocyte receptors in young persons with type I diabetes--effect of physical exercise].

The aim of investigation was the determination of the effect of regular physical exercise of intensity 35% VO2max on glycolysation of proteins, expressed by fructosamine concentration in blood serum and on insulin sensitivity of erythrocyte receptors in children with diabetes mellitus type I. The investigations were performed with 10 young persons with diabetes mellitus type I, during their sanatorium treatment. During 21 days the children effected every day a 20-minutes ergometric exercise of intensity equivalent approximately to 35% VO2max. Before the 3-weeks therapy and after its termination the examined children have performed an ergometric test exercise, with collection of blood samples. Obtained results allow to ascertain, that regular aerobic exercise contributed to the growth of physical efficiency expressed by the VO2max value, reduction in fructosamine level in blood serum, increase in insulin sensitivity of erythrocyte receptor and improved effort tolerance related to glycemia.

Adolescent↗
PubMedDate not supplied

Vitamin E modifies neither fructosamine nor HbA1c levels in poorly controlled diabetes.

OBJECTIVE: To examine the effects of vitamin E on total serum protein glycation (fructosamine), hemoglobin glycation (HbA1c), and serum levels of glucose, total cholesterol, triglycerides, LDL-C, HDL-C, apolipoprotein A1 and apolipoprotein B. MATERIAL AND METHODS: Sixty poorly controlled diabetic patients were randomly assigned to receive either 1200 mg/day of vitamin E or identical placebo capsules during a two month period following a double blind cross-over design with a four week wash-out period between regimens. RESULTS: Seven patients were excluded from the study because of reasons not related to the medication. In the remaining 53 patients, the levels of serum glucose, fructosamine, HbA1c, total cholesterol, HDL-C, LDL-C, Apo A1 and Apo B did not vary significantly with vitamin E as compared with placebo. CONCLUSIONS: No significant effects of vitamin E on any of the parameters evaluated were observed in poorly controlled diabetic patients.

Aged↗
PubMed1998

[Estimated levels of fructosamine in venous blood of pregnant women and in cord blood].

In the study there was estimated maternal (Fm) and cord blood (Fc) fructosamine levels in 151 diabetic (58 PGDM and 93 GDM) and 100 control subjects on the day of delivery. It was found that Fm and Fc levels in PGDM and GDM groups were significantly higher than in the control group. It was also found the significantly positive correlation between Fm and Fc levels in all study groups. It leads to the conclusion that pregnant diabetic women and their fetuses were hyperglycemic during the last 2 weeks of pregnancy. Our results indicate that on the basis of maternal fructosamine levels it is possible to apply on indirect estimation of metabolic status of the fetus.

Adult↗
PubMed2006

Variability in erythrocyte fructosamine 3-kinase activity in humans correlates with polymorphisms in the FN3K gene and impacts on haemoglobin glycation at specific sites.

BACKGROUND: Part of the fructosamines that are bound to intracellular proteins are repaired by fructosamine 3-kinase (FN3K). Because subject-to-subject variations in erythrocyte FN3K activity could affect the level of glycated haemoglobin independently of differences in blood glucose level, we explored if such variability existed, if it was genetically determined by the FN3K locus on 17q25 and if the FN3K activity correlated inversely with the level of glycated haemoglobin. RESULTS: The mean erythrocyte FN3K activity did not differ between normoglycaemic subjects (n = 26) and type 1 diabetic patients (n = 31), but there was a wide interindividual variability in both groups (from about 1 to 4 mU/g haemoglobin). This variability was stable with time and associated (P < 0.0001) with two single nucleotide polymorphisms in the promoter region and exon 6 of the FN3K gene. There was no significant correlation between FN3K activity and the levels of HbA1c, total glycated haemoglobin (GHb) and haemoglobin fructoselysine residues, either in the normoglycaemic or diabetic group. However, detailed analysis of the glycation level at various sites in haemoglobin indicated that the glycation level of Lys-B-144 was about twice as high in normoglycaemic subjects with the lowest FN3K activities as compared to those with the highest FN3K activities. CONCLUSION: Interindividual variability of FN3K activity is substantial and impacts on the glycation level at specific sites of haemoglobin, but does not detectably affect the level of HbA1c or GHb. As FN3K opposes one of the chemical effects of hyperglycaemia, it would be of interest to test whether hypoactivity of this enzyme favours the development of diabetic complications.

Adult↗
PubMed2001

Human fructosamine-3-kinase: purification, sequencing, substrate specificity, and evidence of activity in vivo.

Nonenzymatic glycation appears to be an important factor in the pathogenesis of diabetic complications. Key early intermediates in this process are fructosamines, such as protein-bound fructoselysines. In this report, we describe the purification and characterization of a mammalian fructosamine-3-kinase (FN3K), which phosphorylates fructoselysine (FL) residues on glycated proteins, to FL-3-phosphate (FL3P). This phosphorylation destabilizes the FL adduct and leads to its spontaneous decomposition, thereby reversing the nonenzymatic glycation process at an early stage. FN3K was purified to homogeneity from human erythrocytes and sequenced by means of electrospray tandem mass spectrometry. The protein thus identified is a 35-kDa monomer that appears to be expressed in all mammalian tissues. It has no significant homology to other known proteins and appears to be encoded by genomic sequences located on human chromosomes 1 and 17. The lability of FL3P, the high affinity of FN3K for FL, and the wide distribution of FN3K suggest that the function of this enzyme is deglycation of nonenzymatically glycated proteins. Because the condensation of glucose and lysine residues is an ubiquitous and unavoidable process in homeothermic organisms, a deglycation system mediated by FN3K may be an important factor in protecting cells from the deleterious effects of nonenzymatic glycation. Our sequence data of FN3K are in excellent agreement with a recent report on this enzyme by Delpierre et al. (Diabetes 49:1627-1634, 2000).

Amino Acid Sequence↗
PubMed1990

Fructosamine in relation to maternofetal glucose and insulin homeostasis in gestational diabetes.

The problem in screening for gestational diabetes is recognizing fetuses endangered by hyperinsulinism. 21.8% of patients with gestational diabetes (defined as a glucose peak exceeding 160 mg/dl after an oral glucose load of 1 g per kg body weight) develop fetal hyperinsulinism. Thus, is indicated by an elevated amniotic fluid insulin (AFI) concentration and requires insulin treatment. Since fetal hyperinsulinism can be neither predicted nor ruled out by single parameters of maternal metabolism, every patient with gestational diabetes had to undergo amniocentesis for amniotic fluid analysis. In 110 gestational diabetics and 822 controls, fetal hyperinsulinism was predicted by the combination of the oGTT (greater than or equal to 160 mg/dl) and maternal serum fructosamine (greater than or equal to 2.6 mmol/l) with a sensitivity of 95.8% and a specificity of 91.8%. Thus, 73% of gestational diabetics need not undergo amniocentesis. With a sensitivity of 20.8%, the combination of the oGTT and HbA1c is not useful in identifying hyperinsulinemic fetuses.

Adult↗
PubMed1997

Effects of 4 weeks' administration of pramlintide, a human amylin analogue, on glycaemia control in patients with IDDM: effects on plasma glucose profiles and serum fructosamine concentrations.

The effects of 4 weeks' administration of pramlintide, an analogue of the human hormone amylin, on blood glucose control in 215 patients with insulin-dependent diabetes mellitus were examined in a 4-week, randomized, double-blind, placebo-controlled, parallel-group trial. Pramlintide was administered subcutaneously prior to meals in four dosing regimens: 30 microg four times per day (breakfast, lunch, dinner, and evening snack), 30 microg three times per day (breakfast, lunch and dinner [BLD]), 30 microg three times per day (breakfast, dinner and evening snack [BDS]), and 60 microg twice per day (breakfast and dinner). After 4 weeks of pramlintide 30 microg four times per day administration, there was a statistically significant reduction in the mean 24 h plasma glucose concentration when compared to placebo (-1.4 +/- 0.5 vs 0.3 +/- 0.5 micromol/l, p = 0.009). Serum fructosamine concentrations were reduced 62 +/- 10 micromol/l in the pramlintide 30 mg four times per day group, 43 +/- 7 micromol/l in the pramlintide 30 microg three times per day (BLD) group, 47 +/- 6 micromol/l in the pramlintide 30 microg three times per day (BDS) group, 46 +/- 7 micromol/l in the pramlintide 60 microg twice per day group, and 29 +/- 8 micromol/l by placebo. The incidence of hypoglycaemia was not different in any pramlintide group compared to the placebo group. Nausea, the most frequent adverse event, subsided after the first week of treatment in the majority of patients. In conclusion, pramlintide improved blood glucose control over a 4-week period without increased hypoglycaemia and was well tolerated. Future studies using a longer period of pramlintide administration with assessment of HbA1c as the measurement of glycaemic control are warranted.

Adolescent↗