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Query: UMLS:C0019045 (hemoglobinopathies)
 2,704 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Because of the high prevalence of thrombotic complications in patients with sickle cell anemia (SCA), we investigated platelet function in patients with sickle hemoglobinopathies. Platelet aggregation induced by epinephrine, ADP, and collagen, except for absent secondary wave in 3 of 10 patients with SCA, was qualitatively normal. However, ristocetin-induced platelet aggregation (RIPA) with a final concentration 1.12 mg/ml was markedly abnormal-absent or virtually absent in 9 of 10 patients with SCA, 3 of 3 patients with hemoglobin S-C disease, and 2 of 3 patients with sickle trait. All 8 controls used in these experiments repeatedly demonstrated normal RIPA. Addition of normal plasma failed to correct abnormal RIPA in sickle hemoglobinopathy patients. All patients demonstrated normal RIPA with a ristocetin dose of 2.24 mg/ml and aggregated with bovine fibrinogen. Recombinant mixing experiments demonstrated that washed SCA platelets support RIPA (1.12 mg/ml) when resuspended in normal plasma or high dilutions of SCA plasma, but not in undiluted SCA plasma. Washed normal platelets do not support RIPA (1.12 mg/ml) when resuspended in SCA plasma. These findings suggest the presence of a plasma inhibitor of RIPA in patients with sickle hemoglobinopathies.
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PMID:A plasma inhibitor of ristocetin-induced platelet aggregation in patients with sickle hemoglobinopathies. 59 69

Restriction site polymorphisms are normal inherited variations in DNA that can be readily detected by restriction endonuclease analysis. Currently, 17 such polymorphisms are recognized within a 60 kb (kilobase) stretch of DNA which includes the beta-globin gene complex. Because of their proximity to the beta-globin gene, often these restriction site polymorphisms can be used to predict inheritance of beta-globin variants that produce disease. For example, restriction site polymorphisms can be used for prenatal diagnosis for the large majority of couples at risk of having a child with beta-thalassemia. When each member of such a couple is heterozygous at one or more of these 17 sites, family studies are usually successful in determining which forms of the polymorphism are co-inherited with the beta-thalassemia genes in that particular family. Subsequently, study of fetal DNA isolated from amniocytes obtained by midtrimester amniocentesis or from chorionic villi obtained by first trimester chorion biopsy will reveal which DNA polymorphisms that fetus has inherited. By deductive reasoning one can then predict which beta-globin genes it has co-inherited. Because of the general nature of these polymorphisms, which are related to the beta-globin gene and its variants only because of their proximity on chromosome 11, they are potentially useful in the prenatal diagnosis of any beta-chain hemoglobinopathy. Some hemoglobinopathies (including alpha-thalassemia, sickle cell anemia, and some cases of beta-thalassemia) can be detected directly by DNA analysis. In these cases in utero diagnosis does not need to rely on restriction site polymorphisms, which require preliminary family studies and are not applicable in all at risk pregnancies. Recently, genetic probes, which are necessary for detecting restriction site polymorphisms, have been isolated for sequences of several genes whose protein products are important in blood coagulation. These include probes for all three genes whose polypeptide products combine to form the fibrinogen molecule as well as probes for the prothrombin, Factor IX, Factor VIII, and antithrombin III genes. Defects in these genes are expected to be the causes of afibrinogenemia, prothrombin deficiency, hemophilia B, hemophilia A, and antithrombin III deficiency, respectively. From experience with other genes, it is expected that restriction site polymorphisms within and/or flanking these genes will be found.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Prenatal diagnosis of hemoglobinopathies by DNA analysis. 299 37

Seventeen adult males and females with Hb-SS, Hb-SC (1) and Hb-S Thal (1) hemoglobinopathies were continuously studied for 3 years. Various hematological and biochemical parameters were measured in the venous blood of the subjects for blood gases, CBC profile, blood chemistry (SMA-18), fibrinogen, alpha-HBD and myoglobin levels, percent sickling, blood viscosity, oxygen affinity of whole blood, osmofragility of red blood cells and calcium and zinc contents in plasma and in RBC. The results were compared between those subjects who encountered more frequent vaso-occlusive crisis episodes (frequent sicklers) and those with fewer crisis episodes (infrequent sicklers), along with parameters between crisis and non-crisis states of frequent sicklers. Our studies showed that percent sickling, P50 for O2, CBC profile, PO2, serum calcium, ALP, LDH, alpha-HBD level, zinc and calcium levels in plasma and in RBC varied between crisis and non-crisis states of frequent sicklers and also between frequent sicklers and infrequent sicklers. A logical explanation of such variations may help in understanding the etiology of vaso-occlusive crisis episodes in sickle cell disease.
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PMID:Vaso-occlusive crisis episodes in sickle cell disease. 347 66

The main biological sign of inflammation is an increase in erythrocyte sedimentation rate (ESR). However it can be falsely normal (polyglobulia, cryoglobulinemia, hemoglobinopathy) or spuriously high in the absence of inflammation (anemia, hypergammaglobulinemia). In cases of doubt, the acute phase reactants (APR) should be measured: C reactive protein (CRP), fibrinogen, haptoglobin, alpha 1 acid glycoprotein. They have different kinetics of variation and various degrees of increase (some--the so called "negative" proteins--actually decrease). Several pitfalls can be avoided if it is remembered that the APR themselves can be modified by causes other than inflammation: low fibrinogen in intravascular coagulation, very low haptoglobin in hemolysis, raised orosomucoide in renal insufficiency and elevated transferrin in iron deficiency. Furthermore liver insufficiency or leakage through the kidney or gut lesions can lower them. In some patients, the observed levels of APR are thus the result of opposite trends. In complex cases, these pathological mechanisms are more apparent on profiles which express the concomitant blood levels of several APR in a normalized or comparative manner. In medical practice, ESR serves first and foremost to detect an inflammatory syndrome. CRP is prominent among the APR because its changes show a great sensitivity, are independant of those of ESR and have a time course fitting closely that of the inflammatory processes. Profiles yield detailed information but rarely provide major evidence in the quest of a diagnosis or the choice of a treatment. Because of their cost they are to be used only in difficult cases.
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PMID:[From sedimentation rate to inflammation profile]. 784 87

Red blood cells (RBC) have unique flow-affecting properties--namely, aggregability, deformability and adherence to endothelial cells (EC)--which play major roles in blood flow. Under normal flow-induced shear stress RBC are dispersed, their adherence to EC is insignificant, and they are sufficiently deformable to enable tissue perfusion. However, in pathological conditions that are associated with low-flow states (e.g., trauma, ischemia), elevated plasma components (mainly fibrinogen), or altered RBC properties (e.g., hemoglobinopathies, oxidative stress, inflammation, diabetes), RBC flow properties are altered and present a circulatory risk.
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PMID:The red blood cell in vascular occlusion. 1367 54

We compared routine coagulation markers in six sickle cell trait carriers ((SCT, or AS hemoglobinopathy)--the heterozygous form of sickle cell anemia) and six subjects with normal hemoglobin before and after a prolonged and intense exercise. Blood was sampled at rest and at the end of the entire exercise test to measure coagulation markers (prothrombin time, activated partial thromboplastin time, plasma fibrinogen and antithrombin III activity), hematocrit (Hct) and yield stress (tau(y)). Results obtained at the end of exercise were corrected by the percent change in plasma volume. Blood coagulation markers, Hct and tau(y) were not different between the two groups at rest. Exercise did not change prothrombin time, antithrombin III activity and plasma fibrinogen, decreased activated partial thromboplastin time and increased Hct and tau(y) in the two groups. These parameters were not significantly different between the two groups at the end of exercise, except for plasma fibrinogen which was slightly higher in SCT carriers but in the normal range values. The results have been discussed in relation with some cases of exercise-related sudden death in SCT carriers, reported in several studies. Therefore our results show that the increased risk for clinical complications in certain SCT carriers during exercise seems to be unrelated to higher blood coagulation activity.
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PMID:Effects of strenuous exercise on blood coagulation activity in sickle cell trait carriers. 1809 54