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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemoglobin Mississippi (HbMS: beta 44ser----cys) has anomalous properties that include disulfide linkages with normal beta-, delta-, gamma-, and alpha-chains, and the formation of high molecular weight multimers. While heterozygotes for HbMS are clinically and hematologically normal and carriers of the beta +-thalassemia gene in our family had mild microcytic anemia, the proband with HbMS-beta +-thalassemia had a hemoglobin level of 7 g/dl, mean corpuscular volume (MCV) of 68 fl, reticulocytes of 2-6%, HbF of 18%, marked anisocytosis and poikilocytosis, and splenomegaly, all features of thalassemia intermedia. With oxidant stress, her erythrocytes developed multiple dispersed Heinz bodies, but HbMS was only mildly unstable. HbMS was susceptible to proteolytic degradation in the presence of ATP. The unexpectedly severe clinical findings in HbMS-beta +-thalassemia may result from the proteolytic digestion of HbMS, as well as the excessive alpha-chains characteristic of beta +-thalassemia, which combined provide the increment of cellular damage that results in the phenotype of thalassemia intermedia.
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PMID:Hemoglobin Mississippi (beta 44ser----cys). Studies of the thalassemic phenotype in a mixed heterozygote with beta +-thalassemia. 243 29

A new expert system developed on a Macintosh personal computer using a commercially available artificial intelligence shell was compared with four different discriminant functions (DFs) for the differentiation of microcytic anemia into etiologic categories. Several databases were used with a different composition but all contained at least some samples from thalassemic individuals and from patients with iron deficiency anemia. The DFs analyzed were those proposed by England and Fraser, Green and colleagues, Mentzer, and by Shine and Lal. None of the databases performed satisfactorily when used singly, whereas very high false-positive rates were obtained by one of them. The diagnostic efficiency was somewhat improved by combining several DFs. An expert system using an artificial intelligence "shell" with an "interference engine" was developed using cluster analysis and a set of learning examples. The input necessary for the system to achieve a conclusion consists of MCV, RBC, and RDW as well as a statement as to whether the patient has anemia. Based upon the values of these parameters, the expert system will give an "advice" regarding the probabilities for thalassemia, iron deficiency, and/or other probabilities such as previous transfusions, anemia of chronic disease, laboratory error, etc. In a prospective trial, the system functioned with an accuracy of better than 85%.
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PMID:The use of inference strategies in the differential diagnosis of microcytic anemia. 262 97

The authors studied 119 children with microcytic anemia who were selected by lack of response to a month's treatment with oral iron. Family studies and retesting after further treatment with iron were done in all cases to ensure accurate diagnosis. Seventy-five cases of beta-thalassemia minor (BTM) and 40 cases of iron deficiency were identified. In all 75 cases of BTM, at least one parent had a mean cell volume (MCV) less than 79 microns. In 35 of 40 children with iron deficiency, the MCV of both parents was normal. In contrast, Hb A2 was normal in 15% (11 of 75) of children with BTM, until they received additional treatment with oral iron. The authors conclude that in children with microcytic anemia unresponsive to a month's treatment with oral iron, the MCV of the parents is superior to Hb A2 in discriminating between iron deficiency and heterozygous beta-thalassemia. Repeated testing after additional treatment with oral iron may be needed to ensure accurate diagnosis.
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PMID:Discrimination between iron deficiency and heterozygous beta-thalassemia in children. 370 8

A review of 162 patients with Hodgkin disease disclosed 36 with microcytic anemia (mean corpuscular hemoglobin values [MCV] less than 80 fl). Three patients had iron deficiency, and one had beta-thalassemia. Of the remaining 32 patients, 24 had microcytic anemia at the time of diagnosis of Hodgkin disease, and ten, including two patients with this finding initially, developed microcytic anemia in association with recurrence of Hodgkin disease. Seven patients with Hodgkin disease and normal MCV had normal alpha-to-beta-globin chain ratios (1.0 +/- 0.14). Seven patients with Hodgkin disease and MCV less than 80 fl had significantly lower alpha-to-beta chain ratios (0.66 +/- 0.05). Twelve normal controls and four with iron-deficiency anemia and MCV less than 80 fl had normal ratios. Anemia was corrected, and MCV returned to normal in all patients who responded to therapy for Hodgkin disease. In the two patients studied sequentially, abnormal alpha-to-beta-chain ratio was corrected along with the anemia.
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PMID:Microcytosis in Hodgkin disease associated with unbalanced globin chain synthesis. 375 67

Members of a Cambodian family with an undiagnosed hypochromic, microcytic anaemia were found by haemoglobin and DNA analysis to have five interacting globin gene abnormalities. One child has Hb E and typical Hb H disease, while his mother has the form of Hb H disease associated with Hb Constant Spring interacting with Hb E. Quantitation of Hbs E and A2 by globin chain separation and triton/urea gel electrophoresis support the concept that Hb H/Constant Spring disease is a more severe form of alpha thalassaemia than Hb H disease. This family illustrates how the remarkably high prevalence of globin gene abnormalities in Southeast Asians can give rise to a series of atypical thalassaemic phenotypes, and how they can be defined by direct globin gene analysis.
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PMID:Interaction of five globin gene abnormalities in a Cambodian family. 375 62

In this study we have carried out alpha-globin gene mapping, hemoglobin (Hb) Bart's quantitation serum bilirubin, and red blood cell indices determination in a group of Sardinian appropriate for gestational age premature infants (from 32 to 35 wk gestation) in order to define the incidence in this population of the different alpha-thalassemia syndromes, their expression rate, and the correlation between the alpha-globin genotype and phenotype at this developmental stage. The gene frequencies of deletion (-alpha) and nondeletion (alpha alpha th) alpha-thalassemia were 0.29 and 0.04, respectively, and thus not different from those found in full-term newborns from the same population. The majority of premature newborns with a single alpha-globin gene deletion [(-alpha/alpha alpha) genotype] were hematologically silent. Those who manifested increased Hb Bart's (1.2 to 3.4%) had slightly reduced Hb levels (17.4 +/- 2.6 g/dl), mean corpuscular volume (102.6 +/- 6.3 fl), and mean corpuscular Hb (34.8 +/- 2.0 pg) values. Those infants with the deletion of two alpha-globin structural genes (-alpha/-alpha) showed without exception moderate amount of Hb Bart's in the 3.5-8.1% range and an obvious decrease of Hb levels (16.1 +/- 1.6 g/dl) mean corpuscular Hb (30.6 +/- 3.5 pg), and mean corpuscular volume (88.5 +/- 11.5 fl) values. The only infant with the deletion of 3 alpha-globin structural genes had 25% Hb Bart's associated with a moderate microcytic anemia at birth and developed the clinical picture of Hb H disease. Carriers of nondeletion alpha-thalassemia (alpha alpha/alpha alpha th) showed variable amount of Hb Bart's always associated with thalassemia-like red cell indices.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alpha-thalassemia in premature newborns. 379 1

Mice homozygous for a spontaneous mutation, in which the beta-major globin gene is deleted, have clinical symptoms of beta-thalassemia. These mice have a hypocellular, hypochromic, microcytic anemia that becomes more severe with increasing age. The defective red cell morphology, decreased osmotic fragility of erythrocytes and shortened red cell life span found in beta-thalassemic mice are similar to those observed in human beta-thalassemia. Synthesis of beta-globin is depressed but not as much as might be expected because the expression of the beta-minor globin gene is enhanced to encode two to three times more globin than in normal mice. Splenomegaly, an enlarged pool of stem cells for erythropoiesis, and iron overloading occur in older mice. The fact that these mice remain moderately healthy makes them a very suitable animal model in which to develop and test alternative techniques of gene therapy that could be successfully applied to the treatment of human thalassemia. Homozygous beta-thalassemic mice have large deposits of iron in their tissues, which might make these mice also useful for in vivo tests of the effectiveness and possible long-term side effects of newly developed iron chelators.
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PMID:Hematology of a murine beta-thalassemia: a longitudinal study. 386 Jan 41

Five pregnant Southeast Asian women presenting during a 14-month period with microcytic anemia, preeclampsia, and size-date discrepancies were all ultimately diagnosed as carrying fetuses with homozygous alpha-thalassemia hydrops fetalis. The perinatal complications of this hemoglobin disorder are unique to persons of this ethnic background and include uniform fatality for the affected infant, maternal preeclamptic morbidity, and retained placenta. In this report the obstetric ultrasound findings are presented and the clinical manifestations are discussed, with recommendations made to reduce this emerging public health problem in the United States.
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PMID:alpha-Thalassemia hydrops fetalis: clinical and ultrasonographic considerations. 390 53

An 86-year-old black woman admitted for an elective cataract extraction was found to have moderate hypochromic microcytic anemia. Hematologic evaluation disclosed the presence of hemoglobin SC disease and heterozygous alpha-thalassemia-2 (alpha alpha/alpha-). A red cell density profile of the patient's peripheral blood revealed an absence of the typical uniform shift toward higher-density values seen in hemoglobin SC disease, indicating a "normalization" in the distribution of intracellular hemoglobin types. It is suggested that the co-inheritance of hemoglobin SC disease and heterozygous alpha-thalassemia-2, probably by decreasing the tendency toward intracellular hemoglobin S polymerization, contributed to her prolonged survival and relatively mild clinical course.
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PMID:Hemoglobin SC disease and alpha-thalassemia. Prolonged survival and mild clinical course. 396 52

The diagnostic potential of the combined use of zinc-protoporphyrin (ZPP), mean corpuscular volume (MCV) and haemoglobin measurements for discriminating between iron deficiency anaemia, beta-thalassaemia minor and lead poisoning has been studied. Lead poisoning could be identified by ZPP greater than 50 micrograms/dl in the presence of normal MCV or ZPP greater than 150 micrograms/dl in the presence of microcytosis (MCV less than 80 fl) with a sensitivity of 97% and specificity 94%. Beta-thalassaemia minor was identified by the coexistence of microcytosis and ZPP less than 50 micrograms/dl with a sensitivity of 91% and specificity 79%. Iron deficiency anaemia defined by the combination of microcytosis and ZPP ranging from 50 to 150 micrograms/dl was identified with a sensitivity of 95%, but the specificity was only 51%, with many of the patients overlapping with thalassaemia minor. This problem did not exist in iron-deficiency anaemia with haemoglobin less than 10 g/dl as at that range no patients with uncomplicated thalassaemia minor have been encountered. A great advantage of the combined use of ZPP, MCV and haemoglobin for the initial screening of microcytic anaemia is its ease of performance and low cost. However, this information should only be regarded as presumptive evidence of disease, requiring subsequent confirmation by appropriate direct measurements such as transferrin saturation, serum ferritin, haemoglobin electrophoresis, or blood lead determinations.
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PMID:Combined use of zinc protoporphyrin (ZPP), mean corpuscular volume and haemoglobin measurements for classifying microcytic RBC disorders in children and young adults. 407 41


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