The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Randie R Little - One of the best experts on this subject based on the ideXlab platform.
-
effects of hemoglobin hb e and hbd traits on measurements of glycated hb hba1c by 23 methods
Clinical Chemistry, 2008Co-Authors: Randie R Little, Trefor Higgins, Curt L Rohlfing, Shawn Connolly, Steve Hanson, William E Owen, Mario Dcosta, Veronica Luzzi, Cas Weykamp, William L RobertsAbstract:BACKGROUND: Glycohemoglobin (GHB), reported as hemoglobin (Hb) A1c, is a marker of long-term glycemic control in patients with diabetes and is directly related to risk for diabetic complications. HbE and HbDarethesecondandfourthmostcommonHbvariantsworldwide.WeinvestigatedtheaccuracyofHbA 1c measurement in the presence of HbE and/or HbD traits. METHODS: Weevaluated23HbA1cmethods;9wereimmunoassay methods, 10 were ion-exchange HPLC methods, and 4 were capillary electrophoresis, affinity chromatography, or enzymatic methods. An overall test of coincidence of 2 least-squares linear regression lineswasperformedtodeterminewhetherthepresence of HbE or HbD traits caused a statistically significant difference from HbAA results relative to the boronate affinity HPLC comparative method. Deming regression analysis was performed to determine whether the presenceofthesetraitsproducedaclinicallysignificant effect on HbA1c results with the use of 10% relative bias at 6% and 9% HbA1c as evaluation limits.
-
effects of hemoglobin c and s traits on the results of 14 commercial glycated hemoglobin assays
American Journal of Clinical Pathology, 2008Co-Authors: Shella K Mongia, Curt L Rohlfing, Randie R Little, Steve Hanson, Richard F Roberts, William E Owen, Mario Dcosta, Christine Reyes, Veronica Luzzi, William L RobertsAbstract:Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA 1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA 1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA 1c . Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA 1c ). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits. Glycated hemoglobin, reported as HbA 1c , is a biochemical marker that is routinely used in the management of diabetes mellitus to monitor long-term glycemic control and assess the risk of developing complications. 1-3 The presence of hemoglobin (Hb) C or S trait has been shown to affect the accuracy of some HbA 1c assays. 4-9 In 2004, there were 23.5 million non-Hispanic blacks aged 18 years or older in the United States, 10 of whom at least 10% have HbC or HbS trait. 11 The prevalence of diabetes mellitus, diagnosed and undiagnosed, in non-Hispanic black men is 13.0% and in non-Hispanic black women is 16.3%. 12 This works out to between 305,000 and 383,000 people who have diabetes mellitus and HbC or HbS trait.
-
effects of hemoglobin c and s traits on the results of 14 commercial glycated hemoglobin assays
American Journal of Clinical Pathology, 2008Co-Authors: Shella K Mongia, Curt L Rohlfing, Randie R Little, Steve Hanson, Richard F Roberts, William E Owen, Mario Dcosta, Christine Reyes, Veronica Luzzi, William L RobertsAbstract:Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA1c. Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA1c). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits.
-
the effect of elevated fetal hemoglobin on hemoglobin a1c results five common hemoglobin a1c methods compared with the ifcc reference method
American Journal of Clinical Pathology, 2008Co-Authors: Curt L Rohlfing, Shawn Connolly, J D England, Steven Hanson, Christina M Moellering, Janielle R Bachelder, Randie R LittleAbstract:Hemoglobin A 1c (HbA 1c ) is an important indicator of risk for complications in patients with diabetes mellitus. Elevated fetal hemoglobin (HbF) levels have been reported to interfere with results of some HbA 1c methods, but it has generally been assumed that HbA 1c results from boronate-affinity methods are not affected by elevated HbF levels. None of the previous studies used the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference method as the comparative HbA 1c method. We, therefore, measured HbA 1c in samples with normal and elevated HbF levels by several common assay methods and compared the results with those of the IFCC reference method. HbF levels of more than 20% artificially lowered HbA 1c results from the Primus CLC 330/385 (Primus Diagnostics, Kansas City, MO), Siemens DCA2000 (Siemens Healthcare Diagnostics, Tarrytown, NY), and Tosoh 2.2+ (Tosoh Bioscience, South San Francisco, CA), but not the Bio-Rad Variant II (Bio-Rad Laboratories, Hercules, CA) and Tosoh G7. Physicians and laboratory professionals need to be aware of potential interference from elevated HbF levels that could affect HbA 1c results, including those from boronate-affinity methods.
William L Roberts - One of the best experts on this subject based on the ideXlab platform.
-
effects of hemoglobin hb e and hbd traits on measurements of glycated hb hba1c by 23 methods
Clinical Chemistry, 2008Co-Authors: Randie R Little, Trefor Higgins, Curt L Rohlfing, Shawn Connolly, Steve Hanson, William E Owen, Mario Dcosta, Veronica Luzzi, Cas Weykamp, William L RobertsAbstract:BACKGROUND: Glycohemoglobin (GHB), reported as hemoglobin (Hb) A1c, is a marker of long-term glycemic control in patients with diabetes and is directly related to risk for diabetic complications. HbE and HbDarethesecondandfourthmostcommonHbvariantsworldwide.WeinvestigatedtheaccuracyofHbA 1c measurement in the presence of HbE and/or HbD traits. METHODS: Weevaluated23HbA1cmethods;9wereimmunoassay methods, 10 were ion-exchange HPLC methods, and 4 were capillary electrophoresis, affinity chromatography, or enzymatic methods. An overall test of coincidence of 2 least-squares linear regression lineswasperformedtodeterminewhetherthepresence of HbE or HbD traits caused a statistically significant difference from HbAA results relative to the boronate affinity HPLC comparative method. Deming regression analysis was performed to determine whether the presenceofthesetraitsproducedaclinicallysignificant effect on HbA1c results with the use of 10% relative bias at 6% and 9% HbA1c as evaluation limits.
-
effects of hemoglobin c and s traits on the results of 14 commercial glycated hemoglobin assays
American Journal of Clinical Pathology, 2008Co-Authors: Shella K Mongia, Curt L Rohlfing, Randie R Little, Steve Hanson, Richard F Roberts, William E Owen, Mario Dcosta, Christine Reyes, Veronica Luzzi, William L RobertsAbstract:Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA 1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA 1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA 1c . Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA 1c ). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits. Glycated hemoglobin, reported as HbA 1c , is a biochemical marker that is routinely used in the management of diabetes mellitus to monitor long-term glycemic control and assess the risk of developing complications. 1-3 The presence of hemoglobin (Hb) C or S trait has been shown to affect the accuracy of some HbA 1c assays. 4-9 In 2004, there were 23.5 million non-Hispanic blacks aged 18 years or older in the United States, 10 of whom at least 10% have HbC or HbS trait. 11 The prevalence of diabetes mellitus, diagnosed and undiagnosed, in non-Hispanic black men is 13.0% and in non-Hispanic black women is 16.3%. 12 This works out to between 305,000 and 383,000 people who have diabetes mellitus and HbC or HbS trait.
-
effects of hemoglobin c and s traits on the results of 14 commercial glycated hemoglobin assays
American Journal of Clinical Pathology, 2008Co-Authors: Shella K Mongia, Curt L Rohlfing, Randie R Little, Steve Hanson, Richard F Roberts, William E Owen, Mario Dcosta, Christine Reyes, Veronica Luzzi, William L RobertsAbstract:Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA1c. Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA1c). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits.
Ramón Martínez-máñez - One of the best experts on this subject based on the ideXlab platform.
-
New Cu(II) and Zn(II) complexes of benzolamide with diethylenetriamine: synthesis, spectroscopy and X-ray structures
Polyhedron, 2000Co-Authors: Gloria Alzuet, Sacramento Ferrer-llusar, Joaquín Borrás, Ramón Martínez-máñezAbstract:Abstract New benzolamide (H2bz, 5-phenylsulfonamide-1,3,4-thiadiazole-2-sulfonamide) zinc(II) and copper(II) complexes with diethylenetriamine were synthesized and characterized. The crystal structures of the [M(HBZ)2(dien)] (M=Cu(II), Zn(II); dien=diethylenetriamine) complexes were determined. The metal centre adopts a near regular square pyramidal geometry. The benzolamidate anion acts as a monodentate ligand through the thiadiazole N atom contiguous to the deprotonated sulfonamido group. Spectroscopic properties are in good agreement with the crystal structures. The EPR and electronic spectroscopic studies showed that the copper(II) species doped into the zinc(II) complex adopts a near square planar geometry. The energy and composition of the SOMO of [Cu(HBZ)2(dien)] and of copper substituted [Zn(HBZ)2(dien)] were studied.
Abhijit Chakrabarti - One of the best experts on this subject based on the ideXlab platform.
-
differential thermal stability and oxidative vulnerability of the hemoglobin variants hba2 and hbe
PLOS ONE, 2013Co-Authors: Abhijit Chakrabarti, Dipankar Bhattacharya, Sanghamitra Deb, Madhumita ChakrabortyAbstract:Apart from few early biophysical studies, the relative thermal instability of HbE has been only shown by clinical investigations. We have compared in vitro thermal stability of HbE with HbA2 and HbA using optical spectroscopy. From absorption measurements in the soret region, synchronous fluorescence spectroscopy and dynamic light scattering experiments, we have found thermal stability of the three hemoglobin variants following the order HbE 11.0 in all the three variants. Under oxidative stress conditions in presence of hydrogen peroxide, HbE has been found to be more vulnerable to aggregation compared to HbA and HbA2. Taken together, these studies have shown thermal and oxidative instability of HbE and points towards the role of HbE in the upregulation of redox regulators and chaperone proteins in erythrocyte proteome of patients suffering from HbEbeta thalassemia.
-
Membrane interactions of hemoglobin variants, HbA, HbE, HbF and globin subunits of HbA: effects of aminophospholipids and cholesterol.
Biochimica et biophysica acta, 2007Co-Authors: Poppy Datta, Sudipa Basu Chakrabarty, Amit Chakrabarty, Abhijit ChakrabartiAbstract:The interaction of hemoglobin with phospholipid bilayer vesicles (liposomes) has been analyzed in several studies to better understand membrane-protein interactions. However, not much is known on hemoglobin interactions with the aminophospholipids, predominantly localized in the inner leaflet of erythrocytes, e.g., phosphatidylserine (PS), phosphatidylethanolamine (PE) in membranes containing phosphatidylcholine (PC). Effects of cholesterol, largely abundant in erythrocytes, have also not been studied in great details in earlier studies. This work therefore describes the study of the interactions of different hemoglobin variants HbA, HbE and HbF and the globin subunits of HbA with the two aminophospholipids in the presence and absence of cholesterol. Absorption measurements indicate preferential oxidative interaction of HbE and alpha-globin subunit with unilamellar vesicles containing PE and PS compared to normal HbA. Cholesterol was found to stabilize such oxidative interactions in membranes containing both the aminophospholipids. HbE and alpha-globin subunits were also found to induce greater leakage of membrane entrapped carboxyfluorescein (CF) using fluorescence measurements. HbE was found to induce fusion of membrane vesicles containing cholesterol and PE when observed under electron microscope. Taken together, these findings might be helpful in understanding the oxidative stress-related mechanism(s) involved in the premature destruction of erythrocytes in peripheral blood, implicated in the hemoglobin disorder, HbE/beta-thalassemia.
Curt L Rohlfing - One of the best experts on this subject based on the ideXlab platform.
-
effects of hemoglobin hb e and hbd traits on measurements of glycated hb hba1c by 23 methods
Clinical Chemistry, 2008Co-Authors: Randie R Little, Trefor Higgins, Curt L Rohlfing, Shawn Connolly, Steve Hanson, William E Owen, Mario Dcosta, Veronica Luzzi, Cas Weykamp, William L RobertsAbstract:BACKGROUND: Glycohemoglobin (GHB), reported as hemoglobin (Hb) A1c, is a marker of long-term glycemic control in patients with diabetes and is directly related to risk for diabetic complications. HbE and HbDarethesecondandfourthmostcommonHbvariantsworldwide.WeinvestigatedtheaccuracyofHbA 1c measurement in the presence of HbE and/or HbD traits. METHODS: Weevaluated23HbA1cmethods;9wereimmunoassay methods, 10 were ion-exchange HPLC methods, and 4 were capillary electrophoresis, affinity chromatography, or enzymatic methods. An overall test of coincidence of 2 least-squares linear regression lineswasperformedtodeterminewhetherthepresence of HbE or HbD traits caused a statistically significant difference from HbAA results relative to the boronate affinity HPLC comparative method. Deming regression analysis was performed to determine whether the presenceofthesetraitsproducedaclinicallysignificant effect on HbA1c results with the use of 10% relative bias at 6% and 9% HbA1c as evaluation limits.
-
effects of hemoglobin c and s traits on the results of 14 commercial glycated hemoglobin assays
American Journal of Clinical Pathology, 2008Co-Authors: Shella K Mongia, Curt L Rohlfing, Randie R Little, Steve Hanson, Richard F Roberts, William E Owen, Mario Dcosta, Christine Reyes, Veronica Luzzi, William L RobertsAbstract:Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA 1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA 1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA 1c . Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA 1c ). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits. Glycated hemoglobin, reported as HbA 1c , is a biochemical marker that is routinely used in the management of diabetes mellitus to monitor long-term glycemic control and assess the risk of developing complications. 1-3 The presence of hemoglobin (Hb) C or S trait has been shown to affect the accuracy of some HbA 1c assays. 4-9 In 2004, there were 23.5 million non-Hispanic blacks aged 18 years or older in the United States, 10 of whom at least 10% have HbC or HbS trait. 11 The prevalence of diabetes mellitus, diagnosed and undiagnosed, in non-Hispanic black men is 13.0% and in non-Hispanic black women is 16.3%. 12 This works out to between 305,000 and 383,000 people who have diabetes mellitus and HbC or HbS trait.
-
effects of hemoglobin c and s traits on the results of 14 commercial glycated hemoglobin assays
American Journal of Clinical Pathology, 2008Co-Authors: Shella K Mongia, Curt L Rohlfing, Randie R Little, Steve Hanson, Richard F Roberts, William E Owen, Mario Dcosta, Christine Reyes, Veronica Luzzi, William L RobertsAbstract:Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA1c. Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA1c). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits.
-
the effect of elevated fetal hemoglobin on hemoglobin a1c results five common hemoglobin a1c methods compared with the ifcc reference method
American Journal of Clinical Pathology, 2008Co-Authors: Curt L Rohlfing, Shawn Connolly, J D England, Steven Hanson, Christina M Moellering, Janielle R Bachelder, Randie R LittleAbstract:Hemoglobin A 1c (HbA 1c ) is an important indicator of risk for complications in patients with diabetes mellitus. Elevated fetal hemoglobin (HbF) levels have been reported to interfere with results of some HbA 1c methods, but it has generally been assumed that HbA 1c results from boronate-affinity methods are not affected by elevated HbF levels. None of the previous studies used the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference method as the comparative HbA 1c method. We, therefore, measured HbA 1c in samples with normal and elevated HbF levels by several common assay methods and compared the results with those of the IFCC reference method. HbF levels of more than 20% artificially lowered HbA 1c results from the Primus CLC 330/385 (Primus Diagnostics, Kansas City, MO), Siemens DCA2000 (Siemens Healthcare Diagnostics, Tarrytown, NY), and Tosoh 2.2+ (Tosoh Bioscience, South San Francisco, CA), but not the Bio-Rad Variant II (Bio-Rad Laboratories, Hercules, CA) and Tosoh G7. Physicians and laboratory professionals need to be aware of potential interference from elevated HbF levels that could affect HbA 1c results, including those from boronate-affinity methods.
