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

On 20 consecutive work days during four weeks, one technologist performed 24 microchromatographic determinations of hemoglobin A2 (Hb A2) by each of four methods: the Efremov procedure requiring Tris/HCl buffer, the original Huisman technique with use of glycine developer, and two commercial test kits in which a modified glycine developer is used. The bloood samples tested were obtained from 12 adults with no hematological abnormality and from 12 beta-thalassemia carriers previously diagnosed by familial and hematologic studies. Results by the first method and the two commercial kits (one from Helena Laboratories and one from Isolab, Inc.) did not differ significantly in precision for either the normal or beta-thalassemia trait samples. For both sample types, the second method yielded larger coefficients of variation than those obtained with the other methods. Moreover, the second method was the only one with which values overlapped for normal samples and samples with above-normal Hb A2 concentrations.
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PMID:Microchromatographic methods for hemoglobin A2 quantitation compared. 71 69

A rapid method for separating and quantitating hemoglobin (Hb) variants in cord blood samples using cation high-performance liquid chromatography (HPLC) is described. The procedure is a modification of a previously published method, and uses a weak cation-exchange Brownlee-3CM column and Bis-Tris-KCN-Na acetate developers. A chromatogram can be completed in 10 minutes. The slow-moving variants, Hbs S, C, and O Arab, can be completely separated from each other and are identified by their elution times relative to Hb A. Hb E elutes as a shoulder on the descending side of Hb A, which is characteristic for this variant in this procedure. Differentiation between heterozygous, homozygous, and Hb X-beta+-thalassemia conditions is easily made.
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PMID:Rapid cation-exchange high-performance liquid chromatographic procedure for the separation and quantitation of hemoglobins S, C, and O Arab in cord blood samples. 373 87

Nontransferrin-bound iron (NTBI) was separated from transferrin bound iron (TBI) by DEAE-Sephadex-CDS filtration. TBI is eluted with Tris-NaCl buffer, NTBI that is retained on the column is eluted with citric acid. NTBI was identified in serum from thalassemia and sickle cell patients. Normal serum contained less than 6% NTBI as compared with 15-18% in patient's sera. NTBI levels were decreased significantly after 8 hr chelation with deferoxamine (DFO).
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PMID:Nontransferrin-bound serum iron in thalassemia and sickle cell patients. 379 14

A new test for the laboratory diagnosis of spherocytosis, conventionally called 'Pink test', is presented. This test, semi-quantitatively or quantitatively, determines the hemolysis of small blood samples in a solution containing glycerol (135 mmol/l), NaCl (25 mmol/l), NaN3 (1.5 mmol/l), buffered to pH 6.66 with Bis-Tris (70 mmol/l) and HCl. 'Pink test', as well as 'acidified' glycerol lysis test, were positive in 100% of 42 patients suffering from hereditary spherocytosis, and optimally discriminated them from healthy subjects, showing a diagnostic sensitivity greater than 'standard' glycerol lysis test and osmotic fragility in hypotonic saline solutions of fresh or incubated blood. 'Pink test' was also positive in some cases of renal failure, immunohemolytic anemia, chronic hemoproliferative disorders, normal pregnant women, and negative in other microcytic anemias (beta-thalassemia, iron deficiency anemia). The results do not critically depend on pH of the solution (differently from those obtained with 'acidified' glycerol lysis test), and for this reason they show a good reproducibility.
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PMID:A new test for the laboratory diagnosis of spherocytosis. 643 93

A new cation-exchange HPLC method is described for the separation and quantitation of abnormal human Hbs. The method makes use of Synchropak CM 300, a silica support with carboxylic acid residues, and Bis-Tris-KCN-Na-acetate developers and allows a completion of the chromatogram in 50 to 90 min depending on the sample to be analyzed. Specific chromatographic profiles have been obtained for several beta, alpha, and delta chain variants. The method is useful not only for the quantitation of Hb F and Hb A2 (except in the presence of Hb E) but also provides easy differentiation between simple heterozygotes for a specific abnormality and persons with the same abnormality together with an additional beta-thalassemia heterozygosity. Probably the most important application of the new procedure is in the quantitation of Hb A and the beta chain variants S, C, O-Arab, and E in cord blood samples, thus facilitating the diagnosis of conditions such as AE, EE, AS, SS, S-beta +thal, AC, CC, C-beta +thal, SC, and SO in newborn babies.
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PMID:A new high-performance liquid chromatographic procedure for the separation and quantitation of various hemoglobin variants in adults and newborn babies. 686 67

Commercial microcolumns introduced in 1976 by Helena Laboratories ("Hb A2 Quik Column") and by Isolab, Inc. ("Quik-Sep") provide a rapid, simple, accurate method for quantitation of hemoglobin A2 (Hb A2). However, these kits cannot be used for the quantitation of Hb A2 in the presence of slow-moving variants such as Hb S. Recently, Isolab, Inc., produced a new kit ("Quik-Sep Improved Hb A2 Test") for quantitation of both Hb A2 and Hb S. We compared results obtained with the new Isolab kit to results obtained with the original Tris/HCl method for quantitation of Hb A2 and Hb S. Blood was drawn from persons with sickle cell trait (A/S), sickle cell anemia (S/S), sickle cell/beta+ thalassemia (S/beta+ thal) and sickle cell/beta 0 thalassemia (S/beta 0 thal) and percentages of Hb A2 and Hb S were determined by each method. We found no significant differences in Hb A2 percentages by the two methods, and the coefficients of variation were similar. Both methods showed only slight overlap of Hb A2 values from subjects with some form of beta thalassemia and those with A/S or S/S. However, the Tris/HCl method consistently gave values for Hb S that were higher and closer to those expected, suggesting that the Isolab kit does not accurately quantitate Hb S.
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PMID:Evaluation of a commercial kit for microchromatographic quantitation of hemoglobin A2 in the presence of hemoglobin S. 723 91

We developed a binary gradient high-performance liquid chromatography (HPLC) method for measuring HbA2 in whole blood samples using a Pharmacia Mono Q column (1 mL) and measurement at 415 nm. The assay requires a simple lysis and centrifugation step before injection onto the column. We found good agreement of results between the HPLC method and the Helena column chromatography method. The within batch precision was 2-6% and between batch precision was 4-6%. We found that using 30 mM Tris buffers (pH 7-8) with a sodium chloride gradient resulted in short analysis times and good chromatographic separation of HbA2, HbS and HbA. We conclude that this is a robust assay for the diagnosis of beta-thalassaemia.
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PMID:A rapid anion exchange high-performance liquid chromatography method for the measurement of HbA2 in whole blood. 879 90

The inheritance of the sickle cell gene in combination with a gene for beta(+) thalassemia results in a spectrum of sickle cell-beta(+) thalassemia syndromes with varying levels of hemoglobin A (HbA). Some severe sickle cell-beta(+) thalassemia syndromes have small amounts of HbA, which may be difficult to quantitate in the presence of fetal hemoglobin. A microcolumn chromatographic method, using 0.5 M Tris-acetic acid developers with varying pH values from 9.0 to 6.0, appears to adequately quantitate small amounts of HbA. This method is relatively simple and cheaper than high-performance liquid chromatography, a major consideration in developing countries.
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PMID:Microchromatographic quantitation of hemoglobin A levels in phenotypes of sickle cell-beta(+) thalassemia. 939 Jul 39

The present minireview summarizes recent developments in the field of DNA separations by capillary zone electrophoresis (CZE), as developed by our group. Separation of antisense oligonucleotides in sieving liquid polymers in isoelectric buffers is discussed first. It is shown that the use of isoelectric buffers permits very high voltage gradients (up to 1000 V cm-1) with much reduced transit times and increased resolution of all truncated and failed sequences. Oligonucleotides can also be analysed by zone electrophoresis against a stationary pH gradient (typically a pH 6.5-10 range): if injected at the alkaline end, the sample components experience stacking and zone sharpening due to modulation of charge as the oligonucleotides move along the pH gradient. Oligonucleotides having the same length, but differing by one single nucleotide in the chain, can be separated in free solution (i.e. in the absence of a sieving matrix) at strongly acidic pH values (pH 3.0-3.3) where charge differences due to base protonation are maximized. By working in free solution, it has also been possible to measure accurately the free mobility of DNAs, shown to reach a constant value of 3.75 +/- 0.04 10(-4) cm2 V-1 s-1 at 25 degrees C and in Tris-acetate-EDTA buffer, pH 8.3, above a critical length of ca. 400 base pairs. Finally, detection of point mutations in human genomic DNA is proven to be feasible in nonisocratic CZE, by running temperature-programmed CZE. The temperature gradient is activated within the capillary lumen by voltage ramps during the run, by exploiting joule effects. This technique has been proven to work for all point mutants, from low-, to intermediate-, to high-melters and has been applied to a number of point mutants in cystic fibrosis and thalassemia.
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PMID:Recent advances in capillary zone electrophoresis of DNA. 962 82

Presently genetic analyses for thalassemia types require relatively large amounts of heparinized blood (5 to 10 ml), and transport as well as degeneration of these sample is a problem in the developing world. We have developed a new method to simplify this procedure and obtain DNAs from small specimens. As experimental materials, thinly smeared blood on a glass slide or blood filtered with and adhered on polysthylene telephtalate (PST) fibers were used. These materials could be safely stored without interfering with DNA extraction for up to 3 months. The slide materials were digested with proteinase K, and DNA was extracted with Tris-EDTA-phenol:chloroform and precipitated with absolute ethanol. The PST specimens were washed with physiologic saline and treated in the same manner as described above. Products were easily amplified by PCR and digested with restriction endonucleases for beta thalassemia typing as well as for HLA-DQA1 gene typing. Results obtained by this method correlated well with previously reported incidences for thalassemia and HLA-DQA1 types in Thailand. This method can be used in the routine laboratory because it allows for stable and biosafe genetic analyses.
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PMID:Detection of thalassemia genes using smeared blood film or leukocytes adhering to polysthylene fibers. 964 Jun 14


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