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Your search term(s) "hemoglobinopathies" returned 12 results.

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Glycemic Control and Hemoglobinopathy: When A1C May Not Be Reliable. Diabetes Spectrum. 21(1):46-49. Winter 2008.

This article, from a series that presents patient cases using an evidence-based practice framework, describes a situation in which glycosylated hemoglobin (A1C) measures may not be a reliable marker for glycemic control and hemoglobinopathy. The case patient was an 11-year-old African-American girl newly diagnosed with type 1 diabetes and Hashimoto’s thyroiditis, who was being followed up after her initial hospitalization for diabetic ketoacidosis 2 weeks previously. The author describes her medication compliance, symptoms, concerns about preprandial hypoglycemia, and vital signs. The review of the patient’s laboratory records show that A1C was not measured by the laboratory because of an abnormal hemoglobin peak. The author considers whether hemoglobinopathies affect the clinical reliability of A1C measurement and, if so, what alternate method of assessment should be used for monitoring these patients. The author reports the results of a literature review, discussing hemoglobinopathy in patients with diabetes, variation by laboratory method, assessment of glycemic control using fructosamine, and an evidence grading system for clinical practice recommendations. The author concludes with an overview of the case patient’s present situation and recommendations for improvement of care and ongoing measurement of the child’s blood glucose levels. 33 references.

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Evaluation of Inaccuracies in the Measurement Of Glycemia in the Measurement of Glycemia in the Laboratory, by Glucose Meters, and Through Measurement of Hemoglobin A1c. Clinical Diabetes. 25(2): 43-49. Spring 2007.

This article provides a framework for clinicians who are analyzing the differences between blood glucose measurement as it is obtained from laboratory glucose tests, home glucose meters, and hemoglobin A1c tests. The authors stress that the accurate measurement of blood glucose is extremely important in the diagnosis of diabetes and pre-diabetes, where the laboratory values are crucial; in the management of diabetes, where glucose meter values are crucial; and in attainment of goals in diabetes, where hemoglobin A1c measurement is crucial. The article focuses on pitfalls that may interfere with accuracy of glucose measurement in each of these three areas and how this inaccuracy may be evaluated and managed in the primary care setting. Specific variables that may affect blood glucose measurement can include fasting techniques, serum or plasma glucose samples, centrifugation techniques, the kind of enzyme assay that is used, sampling location, the use of continuous monitors, glucose meter accuracy, the presence of hemoglobinopathy, and being on hemodialysis. The authors present three case examples to illustrate the concepts under discussion. 3 tables. 38 references.

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Haematological Disorders at the Extremes of Life. IN: Provan, D., ed. ABC of Clinical Haematology. Williston, VT: Blackwell Publishing Inc. 2007. pp. 72-77.

This chapter about hematological disorders at infancy and old age is from a book on clinical hematology, written by specialists for nonspecialists. The book is designed to be easy to use and covers the symptoms, investigations, treatment, and management of conditions presenting in day-to-day practice. In this chapter, the authors first discuss hematological disorders in infants, including anemia, hemolytic disease of the fetus and newborn, hemoglobinopathies, thalassemia, sickle cell disease, enzyme deficiencies, membrane defects, sepsis, bleeding and thrombotic disorders, prematurity, thrombocytopenia, neonatal alloimmune thrombocytopenia, transfusion in this age group, neutropenia, polycythemia, and leukemia. A final section covers iron deficiency anemia, megaloblastic anemia, anemia of chronic disease, and malignancies of the blood in people older than 70 years. The authors caution that anemia in the neonate results in reduced tissue oxygenation, metabolic acidosis, and ultimately growth retardation and many other sequelae. Neonatal thrombosis and thrombocytopenia are potentially lethal and prompt diagnosis and management are essential. At the other end of life, elderly people are more susceptible to the effects of anemia, which is often multifactorial and should be investigated and treated appropriately. The chapter is illustrated with full-color photographs, drawings, and charts. 4 figures. 14 tables. 8 references.

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Sickle Cell Trait and Other Hemoglobinopathies and Diabetes: Important Information for Physicians. Bethesda, MD: National Diabetes Information Clearinghouse. 2007. 8 p.

This fact sheet reminds physicians how some people of African, Mediterranean, or Southeast Asian heritage have a variant form of hemoglobin in their red blood cells that affects their diabetes care. The fact sheet describes how the hemoglobin A1c test––for glycosylated hemoglobin––can return false results in people with inherited hemoglobin variants, also called hemoglobinopathies. Physicians are encouraged to consider a change in protocol if a patient’s A1c tests are at odds with blood glucose monitoring results. Reliable A1c tests, in which hemoglobin variants do not cause interference, are available. Readers are referred to the National Glycohemoglobin Standardization Program at www.ngsp.org for more information. One table details the more common hemoglobinopathies, the populations typically affected, the prevalence, and anticipated outcomes. The back cover offers a brief description of the goals and activities of the National Diabetes Information Clearinghouse (NDIC). 2 tables.

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Cardiopulmonary Complications of Sickle Cell Disease: Role of Nitric Oxide and Hemolytic Anemia. IN: Hematology 2005. Washington, DC: American Society of Hematology. 2005. pp. 51-57.

Medical advances in the management of patients with sickle cell disease, thalassemia, and other hemolytic anemias have led to significant increases in life expectancy. Unfortunately, as the patient population with sickle cell disease and thalassemia ages, new chronic complications of these hemoglobinopathies develop. This article reviews the cardiopulmonary complications of sickle cell disease, a problem that is emerging as one of the leading causes of morbidity and mortality in adult sickle cell and thalassemia patients. The authors consider recent data that suggest chronic intravascular hemolysis is associated with a state of endothelial dysfunction, characterized by reduced nitric oxide (NO) bioavailability, pro-oxidant and pro-inflammatory stress, and coagulopathy. These conditions can lead to vasomotor instability and ultimately will produce a proliferative vasculopathy, which causes pulmonary hypertension in adults. Pulmonary hypertension is associated with a high risk of death in patients with sickle cell disease. A final section briefly reviews recommended patient management strategies in this population, focusing on hydroxyurea treatment, monthly transfusion therapy, and the identification and treatment of risk factors associated with pulmonary hypertension. 3 figures. 2 tables. 63 references.

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Hemoglobin E Síndromes. IN: Hematology 2007. Washington, DC: American Society of Hematology. 2007. pp 79-83.

This chapter, from Hematology 2007, reviews hemoglobin (Hb) E syndromes, a heterogeneous group of disorders whose phenotypes range from asymptomatic to severe. Hb E trait and Hb EE are mild disorders; the combination of Hb E and Hb S (Hb SE) results in a sickle cell disease syndrome similar to sickle beta-positive thalassemia. The author reminds readers of the importance of distinguishing Hb E disorders diagnostically because of a marked difference in clinical course among different genotypes. Standard screening tests, including hemoglobin electrophoresis and high-pressure liquid chromatography (HPLC), may suggest other mutations, requiring a familiarity with the laboratory findings. The author reports on a prospective natural history study of E beta-thalassemia in Sri Lanka that suggests that environmental modifiers are prognostically important. The clinical course of E beta-thalassemia is punctuated by acute and chronic complications that may cause serious morbidity and mortality. For example, these patients are at high risk for thromboembolism; iron overload, in nontransfused patients; and cardiopulmonary disease, including pulmonary hypertension. The author concludes with a brief discussion of treatment options, including Hb F–modulating agents and hydroxyurea. Comprehensive care, including genetic counseling, psychological support, and access to new therapies, are necessary for all patients with E beta-thalassemia. 1 figure. 1 table. 42 references.

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Hypercoagulability in Sickle Cell Disease: New Approaches to an Old Problem. IN: Hematology 2007. Washington, DC: American Society of Hematology. 2007. pp 91-96.

This article, from the Hematology 2007 monograph, considers new approaches to the ongoing issue of hypercoagulability in sickle cell disease (SCD). The authors review the characteristics of SCD, including high plasma levels of markers of thrombin generation, depletion of natural anticoagulant proteins, abnormal activation of the fibrinolytic system, and increased tissue factor expression, even in the noncrisis steady state. In addition, platelets and other cellular elements are chronically activated in the noncrisis state. Recent research demonstrating the occurrence of macrovascular thrombotic complications in SCD, as well as supporting the recognition that soluble CD40 ligand is biologically active in SCD, confirms that coagulation and platelet activation may indeed play a role in SCD pathophysiology. However, defining a role for hypercoagulability in SCD requires further understanding of its pathogenesis. The authors conclude by calling for well-controlled clinical trials using anticoagulants and antiplatelet agents and using a variety of clinical endpoints. 2 tables. 55 references.

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Membrane Lipid Alterations in Hemoglobinopathies. IN: Hematology 2007. Washington, DC: American Society of Hematology. 2007. pp 68-78.

This chapter, from the Hematology 2007 monograph, discusses membrane lipid alterations in hemoglobinopathies. The author describes the red blood cell (RBC) membrane as a complex mixture of lipids and proteins. Areas enriched in certain lipids determine proper protein function. Both the composition and organization of the RBC membrane is well maintained. Alterations in the RBC membrane can lead to apoptosis during erythropoiesis or early demise of the cell in the circulation. The mechanisms that govern the maintenance of the lipid bilayer are only recently being unraveled at the individual protein level. Oxidized lipids are rapidly repaired using fatty acids taken up from plasma to maintain membrane integrity. The author discusses the isoforms of a RBC acyl-coenzyme A (CoA) synthase, the family of lysophospholipid acylCoA acyltransferases, the maintenance of phospholipid asymmetry, the enzymes responsible for maintaining membrane lipid organization, and the role of oxidant stress or an increase in cytosolic calcium. All of these normal lipid composition and organization processes may be lost in subpopulations of RBCs in hemoglobinopathies such as sickle cell disease and thalassemia. Despite elaborate antioxidant systems, lipids and membrane proteins, including those that maintain lipid organization, are damaged in these cells. This in turn leads to improper repair of damaged RBC membranes and altered interactions of RBCs with other blood cells and plasma components that play a role in the pathology that defines these disorders. The author concludes that because altered membrane lipids play an important role in the pathology of hemoglobinopathies, the further characterization of the proteins involved in lipid turnover will elucidate the pathways that maintain plasma membrane organization and cellular viability. 30 references.

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Role of Adhesion Molecules and Vascular Endothelium in the Pathogenesis of Sickle Cell Disease. IN: Hematology 2007. Washington, DC: American Society of Hematology. 2007. pp 84-90

This article, from the Hematology 2007 monograph, explores the role of adhesion molecules and the vascular endothelium in the pathogenesis of sickle cell disease (SCD). The author notes that various research studies now support the hypothesis that vaso-occlusion and several of the complications of SCD arise, at least in part, from adhesive interactions of sickle red blood cells, leukocytes, and the endothelium. Topics include the sites of vaso-occlusion and the endotheliopathy of SCD, the contribution of inflammation and hypercoagulability to vaso-occlusion, targeting cell adhesion as a therapeutic strategy, the possible role for anti-inflammatory agents, and antisickling therapy. The author concludes that, if this relationship can be further elucidated, it is likely that future therapies for SCD might target one or more of these interactions. These therapies might include drugs such as transport channel inhibitors to prevent red blood cell (RBC) dehydration, sickling, and hemolysis; statins and other anti-inflammatory agents; inhibitors of adrenergic receptors; and antiplatelet agents and anticoagulants. 1 figure. 1 table. 53 references.

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Reduced-Intensity Regimens in Allogeneic Hematopoietic Stem Cell Transplantation for Hemoglobinopathies. Washington, DC: American Society of Hematology. 2006. pp. 398-401.

This article reviews the use of reduced-intensity regimens in allogeneic hematopoietic stem cell transplantation (HSCT), a technique used for hemoglobinopathies. HSCT is the only well-established curative therapy for patients with hemoglobinopathies, which, in the last 20 years, has been mainly performed from an HLA-matched, related donor, using bone marrow as source of hematopoietic progenitors. More recent studies indicate that HSCT from unrelated donors may offer results comparable to those obtained with HLA-identical family donors, provided that stringent criteria of compatibility are employed for selecting the donor. A reduced preparation regimen consists of immune suppression—mainly achieved with the use of purine analogues such as fludarabine-with minimal or limited host myeloablation, but sufficient to achieve donor chimerism. These treatments may be of particular interest in patients who are not eligible for standard allograft procedures due to older age or poor medical condition. However, few reports have demonstrated the feasibility of using reduced-intensity preparative regimens and there have been many treatment failures, mainly due to the lack of sustained donor engraftment. Despite these limitations, some of the concepts obtained from the use of reduced intensity regimens, such as the substitution of fludarabine for cyclophosphamide, may be important to further improve the outcome of patients with hemoglobinopathies, especially of those with poor prognostic characteristics, given HSCT. 45 references.

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Guidelines And Recommendations for Laboratory Analysis in the Diagnosis And Management of Diabetes Mellitus. Clinical Chemistry. 48(3): 436-472. March 2002.

Multiple laboratory tests are used in the diagnosis and management of patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially. An expert committee drafted evidence-based recommendations for the use of laboratory analysis in patients with diabetes. An external panel of experts reviewed a draft of the guidelines, which were modified in response to the reviewers' suggestions. A revised draft was posted on the Internet and was presented at the AACC Annual Meeting in July, 2000. The recommendations were modified again in response to oral and written comments. The guidelines were reviewed by the Professional Practice Committee of the American Diabetes Association. Measurement of plasma glucose remains the sole diagnostic criterion for diabetes. Monitoring of glycemic control is performed by the patients, who measure their own plasma or blood glucose with meters, and by laboratory analysis of glycated hemoglobin. The potential roles of noninvasive glucose monitoring, genetic testing, autoantibodies, microalbumin, proinsulin, C-peptide, and other analytes are addressed. The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are of minimal clinical value at the present time, and measurement of them is not recommended. 7 tables. 267 references.

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Effects of Hemoglobin Variants and Chemically Modified Derivatives on Assays for Glycohemoglobin. Clinical Chemistry. 47(2): 153-163. 2001.

Glycohemoglobin (gHb), measured as hemoglobin (Hb) A(1c) or as total gHb, provides a common means for assessing long-term glycemic control in individuals with diabetes mellitus. Genetic variants and chemically modified derivatives of Hb can profoundly affect the accuracy of these measurements, although effects vary considerably among commercially available methods. The prevalence of genetic variants such as HbS, HbC, and HbE, and chemically modified derivatives such as carbamyl-Hb among patient populations undergoing testing is not insignificant. Clinical laboratories and sites responsible for point-of-care testing of gHb need to be aware of the interferences produced in assays by these Hbs. We conducted a review of the literature describing the effects of variant Hbs on gHb assay methods commonly used in clinical laboratories. This review summarizes the documented effects of both common and uncommon Hb variants and derivatives on the measurement of gHb. Where known, we discuss mechanisms of interference on specific assays and methodologies. We specifically address effects of commonly encountered Hbs, such as carbamyl-Hb, HbS, HbC, HbE, and HbF, on assays that use cation-exchange chromatography, immunoassays, or boronate affinity methods for measuring gHb. A variety of patient and laboratory related factors can adversely affect the measurement of gHb in patients harboring Hb variants or derivatives. Identification of the variant or derivative Hb before or during testing may allow accurate measurement of gHb by the selection of a method unaffected by the given variant or derivative. However, laboratories should make available alternative, non-Hb-based methods for assessing long-term glycemic control in individuals with HbCC, HbSS, or HbSC disease, or with other underlying disorders where the concentration of gHb does not accurately reflect long-term glycemic control. 3 tables. 61 references.

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