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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unusual increases in the minor hemoglobin components (Hb AIa, b, c) known to be elevated in diabetes mellitus were found in states of relative or absolute insulinopenia: diabetic ketoacidosis, steroid-induced diabetes, insulin-dependent diabetes in cystic-fibrosis patients, and cystic fibrosis occurring in infants who have a marked suppression of insulin secretion. In ketoacidotic diabetics, it required at least a month for high Hb AI levels (16.9 +/- 2.6 per cent) to stabilize at nonacidotic levels (12.8 +/- 0.3 per cent), suggesting that decreases occur only as new red cells form under conditions less favorable to Hb AI synthesis. Abnormal amounts os Hb A and Hb AI resisted removal from diabetic red-cell membranes by low ionic buffers but yielded to hypotonic Tris buffer. Their removal resulted in simultaneous elution of peripheral and integral membrane proteins. It is suggested that Hb so firmly bound could reduce membrane elasticity and cell deformability, characteristics so vital to normal red cell movement through the microvasculature.
Diabetes 1976
PMID:Hemoglobin AIc levels in insulin-dependent and -independent diabetes mellitus. 82 66

Seven patients had sickle cell trait (hemoglobin AS) and vasoproliferative retinopathy. The retinal abnormalities in these seven patients were indistinguishable from those seen in patients with clinically significant sickling hemoglobinopathies (sickle cell-hemoglobin C disease, hemoglobin S-thalassemia disease, and sickle cell anemia). All seven patients also had some evidence of associated systemic disease such as diabetes, syphilis, tuberculosis, or sarcoidosis. In the presence of an associated systemic disease, marked retinopathy can occur in the ordinarily benign condition of sickle cell trait.
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PMID:Proliferative retinopathy in sickle cell trait. Report of seven cases. 84 50

Seven patients with diabetes mellitus were hospitalized and their blood sugar concentrations regulated as a result of fasting blood sugar, sugar around meals, urinary sugar, and hemoglobin AIC assays. Erythrocyte half-life as measured by 51 Cr increased in all patients from a mean of 27 days to 31 days, while hemoglobin AIC levels decreased from a mean of 10.1% to 5.6%. Leukocyte adherence increased in all patients from a mean of 28% to 51%. Most striking were the changes observed in platelet function in response to epinephrine. The length of the secondary lag phase of platelet aggregation, after a stimulus with final concentration of 70 muM of epinephrine, increased from a mean of 19 seconds to 65 seconds. Studies in additional patients confirmed an inverse correlation between hemoglobin AIC concentration and the secondary lag phase (r = 0.87, P less than 0.001). These studies found that certain secondary sequelas of diabetes can be corrected by strict carbohydrate control and confirmed that hemoglobin AIC assays provide a useful means of showing the degree of control of glucose metabolism in diabetic patients.
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PMID:Reversible hematologic sequelae of diabetes mellitus. 84 4

Studies in 10 nonketotic diabetic subjects (five juvenile- and five adult-onset) before and after control of carbohydrate metabolism showed a high degree of correlation between hemoglobin AIc (HbAIc) concentrations and serum triglyceride levels. Serum triglyceride levels were found to correlate more closely with Hb AIc (r = 0.91, p less than 0.001) than did serum cholesterol (r = 0.47, p greater than 0.05), thus indicating a more direct relationship to carbohydrate metabolism.
Diabetes 1977 May
PMID:Correlation of serum triglyceride levels and hemoglobin AIc concentrations in diabetes mellitus. 85 30

Hemoglobin AIc is a minor component of normal adult erythrocytes whose concentration is elevated approximately 2-fold in patients with diabetes mellitus. Previous work suggested that the unique structural feature of hemoglobin AIc is the presence of a low molecular weight sugar moiety at the NH2-terminal valine of the beta chain. In this study the structure of the carbohydrate moiety and the nature of its linkage of the beta chain were investigated. Enzymatic digestion of borohydride-reduced betaAIc chains followed by ion exchange chromatography led to the isolation of two distinct NH2-terminal glycovalylhistidines. Comparison of these glycodipeptides with synthetic glycovalylhistidines by thin layer chromatography, gas-liquid chromatography, and proton magnetic resonance spectroscopy gave direct evidence that the naturally derived materials correspond to glucitol and mannitol valylhistidines. Model reactions showed that glucose and mannose react with valine under mild conditions to form an adduct which upon sodium borohydride reduction yields in both cases glucitol and mannitol valines. This suggests a common intermediate, 1-deoxy-1-(N-valyl)fructose, for both reactions. From these studies we conclude that hemoglobin AIc has, as the NH2 terminus of the beta chain, 1-deoxy-1-(N-valyl)fructose. The possible biosynthetic pathways of hemoglobin AIc are discussed.
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PMID:Structure of carbohydrate of hemoglobin AIc. 85 40

The incubation of dialyzed hemoglobin A with a number of phosphorylated glycolytic intermediates leads to the formation of covalent hemoglobin adducts that co-chromatograph with hemoglobin AIb. Phosphorylated hexoses (glucose-6-P, fructose-6-P, fructose-1,6-P2) and trioses (glyceraldelyde-3-P, dihydroxyacetone-P) containing a free aldehyde or ketone can glycosylate hemoglobin A nonenzymatically. From 7 to 12% of the hemoglobin can be modified after a 72-h incubation of an equimolar mixture of hemoglobin A and the phosphorylated intermediate. No significant formation of adduct was seen with a sugar alone (glucose, fructose) or glycolytic intermediate which had a blocked aldehyde (glucose-1-P, glucose-1,6-P2, UDP-glucose). The addition of an equimolar amount of 2,3-diphosphoglycerate reduced adduct formation. Evidently, the phosphate is needed to orient and stabilize the intermediate in the bisphosphoglycerate pocket of hemoglobin so that the addition reaction can proceed. All of the hemoglobin A adducts were indistinguishable form hemoglobin AIb by ion exchange chromatography and isoelectric focusing. The hemoglobin A-glucose-6-P adduct and hemoglobin AIb had a NaB3H4-reducible linkage in the beta chain. The concentration of hemoglobin AIb is elevated in patients with diabetes mellitus. This presumably reflects the increased concentrations of glycolytic intermediates (glucose-6-P, fructose-6-P, fructose-1,6-P2, dihydroxyacetone-P) which were found to be significantly elevated in the red cells of diabetic patients as compared with normal controls.
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PMID:Nonenzymatic glycosylation of hemoglobin. 85 10

We studied the increased levels of hemoglobins AIa+Ib and AIc in five hospitalized diabetic patients to determine whether changes in diabetic control would cause parallel changes in the levels of these hemoglobins. Before control of diabetes the mean fasting blood sugar for all patients was 343 mg per deciliter (range, 280 to 450), and hemoglobin AIc concentration 9.8 per cent (range, 6.8 to 12.1). During optimal diabetic control the blood sugar concentration was 84 mg per deciliter (range, 70 to 100), and hemoglobin AIc concentration 5.8 per cent (range, 4.2 to 7.6). Hemoglobin AIc concentration appears to reflect the mean blood sugar concentration best over previous weeks to months. The periodic monitoring of hemoglobin AIc levels provides a useful way of documenting the degree of control of glucose metabolism in diabetic patients and provides a means whereby the relation of carbohydrate control to the development of sequelae can be assessed.
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PMID:Correlation of glucose regulation and hemoglobin AIc in diabetes mellitus. 93 40

The minor hemoglobin components, hemoglobin AIa+b and hemoglobin AIc, were measured in the 10% youngest and 10% oldest erythrocytes of 15 normal and 14 diabetic subjects. Erythrocyte fractions were obtained by centrifugation in isopyknic concentrations of dextran: 28.5% of 40,000-mol wt dextran yeilded the 10% lightest of young cells, and 30.5% dextran provided the 10% heaviest or old erythrocytes. Both normal and diabetic erythrocytes contain increased amounts of Hb AIa+b and Hb AIc in old as compared to young cells. In normal subjects, young cells contained 1.2+/-0.2%, and old cells contained 1.8+/-0.4% Hb AIa+b. Corresponding values for diabetic cells were 1.7+/-0.6 and 2.6+/-0.9%. Hb AIc increased from 3.1+/-0.8 to 6.0+/-1.1% in normals and from 5.1+/-2.1 to 10.1+/-3.7% in diabetics. The results indicate that both cell age and diabetes are significant determinants of the amounts of Hb AIa+b and Hb AIc.
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PMID:Red cell age-related changes of hemoglobins AIa+b and AIc in normal and diabetic subjects. 96 89

Hemoglobin AIc, a normal minor hemoglobin, has glucose linked by a Schiff base to the N-terminal end of the beta chain. The glucose interferes with the binding of 2,3 diphosphoglycerate, probably resulting in an increased affinity of that hemoglobin for oxygen. Hb AIc is increased to twice normal levels in juvenile-onset (insulin-dependent) diabetes. In the present studies, the Hb AIc, when expressed as per cent of total hemoglobin, was found to be elevated slightly in pregnany normal (m = 6.97 per cent), pregnant nondiabetic obese (m = 6.89 per cent), and gestationally diabetic subjects (m = 8.77 per cent) above that of normal females (m = 5.68 per cent). A remarkable difference was observed between the nonpregnant diabetics (m = 12.77 per cent) and the pregnant diabetics (m = 8.46 per cent). This decrease in the level of Hb AIc in diabetics who are pregnant more than 30 weeks may reflect either a better state of diabetic control and/or a compensatory mechanism to protect the fetus by facilitating oxygen exchange from mother to fetus.
Diabetes 1976 Dec
PMID:Effects of pregnancy on hemoglobin AIc in normal, gestational diabetic, and diabetic women. 99 31

Adult diabetic mice (C57Bl/KsJ--db/db) have increased amounts of a minor hemoglobin in their peripheral blood compared to wild-type (+/+) mice. This increase is analogous to the 2-fold increase of a glycohemoglobin with similar chromatographic mobility (Hb AIc) seen in the blood of patients with diabetes mellitus. Although the exact chemical nature of human or mouse Hb AIc is unknown, both contain a sodium-borohydride-reducible linkage on the beta chain which is a presumed Schiff base between a sugar moiety and the protein. The db/db animals, which have normal amounts of mouse Hb AIc at weaning, show the increase approximately 4 weeks after the onset of the signs of diabetes. This rise is brought about by an increase in a circulating factor that determines directly or indirectly the synthesis of mouse Hb AIc as a post-synthetic modification of Hb A. Evidence for this was obtained by showing that the rate of synthesis of the modified Hb is linear for at least the first 50 days of the life of the red cell and that the rate of synthesis is dependent on the environment in which the cells circulate. Thus the rate of mouse Hb AIc synthesis in +/+ cells is greater when those cells circulate in a db/db host than when they circulate in a +/+ host. The nature of the humoral factor is unknown. If glycosylations of basement membrane proteins and hemoglobin proceed via a common mechanism, then the monitoring of Hb AIc could provide a useful model for studying the early events of basement membrane thickening.
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PMID:Synthesis of hemoglobin AIc in normal and diabetic mice: potential model of basement membrane thickening. 105 58


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