Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Certain single base substitutions causing genetic diseases or resulting in polymorphisms linked to mutant alleles, alter a restriction enzyme cleavage site and can therefore be detected in total genomic DNA using DNA blots. Many base substitutions do not lead to an altered restriction site, but these can be detected using synthetic oligonucleotides as hybridization probes if the DNA sequence surrounding the base substitution is known. In the case of beta-thalassaemia, where 22 different single base mutations have been identified, a large number of probes would be required for diagnosis. An approach which was used to detect mutations in viral DNA involves the S1 nuclease treatment of heteroduplexes formed between wild-type and mutant DNA. Although certain single base mismatches are cleaved by S1 nuclease (ref. 11 and T. Shenk, personal communication), many other mismatches examined by this procedure are not cleaved (B. Seed, personal communication; R.M.M., unpublished data). Heteroduplexes between mutant and wild-type subgenomic fragments of double-stranded reovirus RNA migrate slower than the corresponding homoduplexes in polyacrylamide gels containing 7 M urea, but it is not known whether this method is applicable to DNA heteroduplexes containing single base mismatches. Here we describe a procedure that involves the electrophoretic separation of DNA heteroduplexes in a well-characterized gel system. We show that four different human beta-thalassaemia alleles with known single base mutations can be detected with as little as 5 micrograms of total genomic DNA. The method should be useful in the localization and diagnosis of mutations associated with genetic diseases.
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PMID:Detection of single base substitutions in total genomic DNA. 396 55

The gamma G/gamma A ratio was determined on 50 cord blood samples from normal newborns and in 28 beta-thalassemia homozygotes among the Lebanese population, using electrophoresis on acrylamide-bisacrylamide gels containing Triton X-100, urea, and 2-mercapto-ethanol. 2-Mercapto-ethanol was found to be the most effective reducer, giving good resolution and a clean background. As the concentration of Triton X-100 was critical in this study, a concentration of 500 microliters of Triton X-100/25 ml of reaction mixture was found to be optimal. In our 50 cord blood samples, the mean total Hb was 20 g/dl, with a range of 12-26. The mean fetal Hb (HbF) level was 64%, and the range 50-90%. The mean value for gamma G/gamma G + gamma A was 0.75. All beta-homozygotes had an elevated HbF, ranging from 7.7-99.3%, and their mean gamma G/gamma G + gamma A was 0.64. Only two out of 28 had gamma G/gamma G + gamma A ratio of 0.5; in the rest it was 0.60 or greater. This may be due to the greater resistance of erythrocytes with higher HbF and higher gamma G/gamma A destruction.
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PMID:Determination of the gamma G/gamma A ratio in homozygous beta-thalassemic patients among a Lebanese population. 608 41

In a Greek family three cases of beta-thalassaemia intermedia were diagnosed as resulting from the interaction of a typical high HbA2-beta-thalassaemia with an atypical (silent) beta-thalassaemia gene. Following electrophoresis of globins on an acid-urea-Triton-acrylamide system, an otherwise silent beta-like variant was revealed in the carriers of the atypical thalassaemia gene and in the intermediates; it amounted to 33% of the non-alpha chains in the former and to c. 75% in the latter. The provisional name Hb Knossos is suggested for this abnormality.
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PMID:'Silent' beta-thalassaemia caused by a 'silent' beta-chain mutant: the pathogenesis of a syndrome of thalassaemia intermedia. 710 38

Determination of the biosynthetic beta/gamma ratio in samples of fetal blood is used for prenatal diagnosis of thalassemia. The current method, carboxymethyl cellulose chromatography (CMC), is cumbersome, slow, and expensive. Radiolabelled globin chains (A gamma, G gamma, beta, and alpha) can also be separated by electrophoresis in slab gels containing polyacrylamide, acid, urea, and Triton X-100. The radioactive bands are detected by fluorography. We determined the beta/gamma ratio in 24 samples of blood from fetuses at risk for beta thalassemia. CMC column data were compared with quantitations from fluorograms of slab gels. The beta/gamma synthetic ratios correlated (r=0.91), although the ratios were slightly less by gel than by column. The gel method is simple, inexpensive, and permits up to a dozen simultaneous analyses. Confirmatory CMC columns need only be run if the beta/gamma ratio is between 0.01 and 0.03 by gel.
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PMID:Globin chain electrophoresis for prenatal diagnosis of beta thalassemia. 725 78

The globin chains of human embryonic, fetal, and adult hemoglobins can be separated by electrophoresis on gels containing polyacrylamide, acid, urea, and Triton X-100. Whole hemolysates are used, and only microgram quantities are required. The order of the major human erythrocyte proteins, from anode to cathode, is zeta, epsilon, carbonic anhydrase, A gamma, delta and G gamma together, beta, and alpha. Protein composition can be measured on Coomassie blue-stained disc gels, and protein synthesis on fluorograms of slab gels containing 3H-leucine-labelled material. These gels have been used to examine the ratio of G gamma to A gamma in blood from fetuses and newborn infants, and to suggest that the switch from A gamma to G gamma during ontogeny may not be linked to the switch from gamma to beta production. beta/gamma synthetic ratios were determined in fetuses at risk for thalassemia. Embryonic and fetal globin synthesis ratios were measured in hemin-induced human erythroleukemia cells K562 in tissue culture. Fetal globin synthesis and the proportion that was of the "fetal" type (G gamma approximately 70%) was studied in erythroid colonies grown in plasma clot cultures from adult, newborn, and 6 month infant specimens. The gels provide a rapid, simple, and inexpensive approach to many problems of globin composition and synthesis.
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PMID:Gel electrophoretic separation of globin chains. 727 69

Intravenous arginine butyrate has been shown to increase fetal hemoglobin (HbF) in sickle cell and thalassemia patients. Recently, we observed that sodium 4-phenylbutyrate, a drug administered orally to treat urea cycle disorders, increases HbF production in nonanemic children and adults. We treated six subjects with sickle cell disease over a period of 14 to 179 days. All subjects received their initial therapy of 9 to 13 g/m2/day as 0.5-g tablets of sodium 4-phenylbutyrate as inpatients. All subjects showed a rapid increase in the percentage of F-reticulocytes (pretreatment, 1% to 20%; posttreatment, 10% to 44%). Four subjects were treated only 11 to 25 days as inpatients. Two of these four subjects failed to respond to the outpatient component because of their inability to maintain an intake of 30 to 40 tablets per day. One subject (C) developed a rash at day 10 and discontinued treatment at day 14. Another subject (B) was transfused for a painful crisis on day 25. Subject A, treated for 179 days, has an increased percentage of F cells, from 54% to 77%, and increased HbF levels, from 10.6% to 18%. Subject F, treated for 154 days, has an increased percentage of F cells, from 59% to 73%, and an increased percentage of HbF, from 10.4% to 16%. All subjects showed some increase in weight. Subject A developed mild transient ankle edema. Myelotoxicity was not seen in any treated patient. Oral administration of sodium 4-phenylbutyrate rapidly increases F-cell production in sickle cell disease.
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PMID:Induction of fetal hemoglobin production in subjects with sickle cell anemia by oral sodium phenylbutyrate. 751 15

Butyrate analogues have been shown to increase fetal hemoglobin (HbF) production in vitro and in vivo. Sodium phenylbutyrate (SPB), an oral agent used to treat individuals with urea-cycle disorders, has been shown to increase HbF in nonanemic individuals and in individuals with sickle cell disease. We have treated eleven patients with homozygous beta thalassemia (three transfusion dependent) and one sickle-beta-thalassemia patient with 20 g/d (forty 500-mg tablets) of SPB for 41 to 460 days. All patients showed an increase in the percent of F reticulocytes associated with treatment, but only four patients responded by increasing their Hb levels by greater than 1 g/dL (mean increase, 2.1 g/dL; range, 1.2 to 2.8 g/dL). None of the transfusion-dependent thalassemia subjects responded. Increase in Hb was associated with an increase in red blood cell number (mean increase, 0.62 x 10(12)/L), and mean corpuscular volume (mean increase, 6 fL). Changes in percent HbF, absolute HbF levels, or alpha- to non-alpha-globin ratios as measured by levels of mRNA and globin protein in peripheral blood did not correlate with response to treatment. Response to treatment was not associated with the type of beta-globin mutation, but baseline erythropoietin levels of greater than 120 mU/mL was seen in all responders and only two of eight nonresponders to SPB. Compliance with treatment was greater than 90% as measured by pill counts. Side effects of the drug included weight gain and/or edema caused by increase salt load in 2/12, transient epigastric discomfort in 7/12, and abnormal body odor in 3/12 subjects. Two splenectomized patients who were not on prophylactic antibiotics developed sepsis while on treatment. We conclude that SPB increases Hb in some patients with thalassemia, but the precise mechanism of action is unknown.
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PMID:Oral sodium phenylbutyrate therapy in homozygous beta thalassemia: a clinical trial. 752 72

In both sickle cell (SS) anemia and beta-thalassemia (beta-thal), an increase in fetal hemoglobin (HbF) ameliorates the clinical symptoms of the underlying disease. Several pharmacologic agents have been used to elevate HbF levels in adults; however, concerns regarding adverse effects of the prevailing drugs raise an urgent need for other agents capable of stimulating HbF production. We show here that sodium phenylacetate (NaPA) and its precursor, sodium 4-phenylbutyrate (NaPB), can enhance HbF production in cultured erythroid progenitor derived from normal donors and patients with SS anemia or beta-thal, when used at pharmacologic concentrations. Treatment resulted in (1) reduced cell proliferation, (2) elevated hemoglobin (Hb) content per cell (mean cellular Hb [MCH]), and (3) an increased proportion of HbF produced, associated with elevated levels of gamma-globin mRNA. Moreover, the active phenyl-fatty acids, with NaPA as a prototype, potentiated HbF induction by other drugs of clinical interest, including hydroxyurea (HU), sodium butyrate, and 5-azacytidine (5AzaC). Efficacy could be further enhanced by introducing chlorine substituents at the phenyl ring to increase drug lipophilicity. Our findings indicate that NaPA and NaPB, both already proven safe and effective in treatment of children with urea cycle disorders, might benefit also patients with severe hemoglobinopathies. The two-phase liquid culture procedure used in this study should prove valuable in further studies exploring the mechanisms of HbF induction by these agents, and might provide an assay to predict patient response in the clinical setting.
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PMID:Enhanced fetal hemoglobin production by phenylacetate and 4-phenylbutyrate in erythroid precursors derived from normal donors and patients with sickle cell anemia and beta-thalassemia. 769 Dec 51

The behavior of different sieving polymers for unambiguous determination of point mutations in genomic DNA, based on electrophoresis in thin capillaries, is evaluated. High melters from thalassemia patients are separated by exploiting the principle of denaturing gradient gel electrophoresis, in fact, of its variant utilizing temperature gradients (TGGE), along the migration path, encompassing the melting points of both homo- and heteroduplex, polymerase chain reaction (PCR)-amplified DNA fragments. Unlike TGGE, where the temperature gradient exists along the separation space, the denaturing temperature gradient in the fused-silica capillaries is time-programmed, so as to reach the Tm's of all species under analysis prior to electrophoretic transport past the detector window. The DNA fragments are injected in a capillary maintained (by combined chemical and thermal means) just below the expected Tm values. The deltaT applied is rather minute (1-1.5 degrees C) and the temperature gradient quite shallow (e.g., 0.05 degrees C/min). The denaturing thermal gradient is generated internally, via Joule heat produced by voltage ramps. This method is applied to the analysis of the most common point mutations in thalassemias, characterized by being high melters (in the temperature range of 60-62 degrees C) in presence of 6 M urea. Point mutants are fully resolved into a spectrum of four bands only when poly(N-acryloylaminopropanol) and hydroxyethylcellulose are used. However, the former offers the best separation capability at such high temperatures.
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PMID:Temperature-programmed capillary electrophoresis for the analysis of high-melting point mutants in thalassemias. 919 97

The purpose of this study was to characterize the effects of sodium 4-phenylbutyrate (phenylbutyrate) on the proliferation, morphology, migration and invasiveness of malignant glioma cells in vitro. Phenylbutyrate is a novel differentiating and cytotoxic compound used clinically with low toxicity in the treatment of beta-thalassemia, sickle cell anemia and urea cycle disorders. Preliminary clinical trials testing phenylbutyrate as an anti-cancer agent have included patients with malignant glioma. However, little information is available regarding the effects of phenylbutyrate on glioma cells, particularly with respect to the expression of genes important in the pathogenesis of glial malignancy. In experiments reported here, glioma cell lines and explant cells from a tumor patient were exposed to 2, 4 and 8 mM phenylbutyrate and compared to untreated control cells. The effect on cellular proliferation was assessed using cell counts and DNA flow cytometry. Changes in morphology were evaluated using vimentin staining. Scratch and Matrigel assays were performed to assess changes in cellular migration and invasiveness. Finally, Northern blot analysis was used to study c-myc and urokinase expression. Phenylbutyrate was found to have dose-dependent inhibitory effects on glioma cell proliferation, morphology, migration, invasiveness and c-myc and urokinase expression. Mean growth-inhibitory (IC50) phenylbutyrate concentrations ranged from 0.5 mM for T98G cells to 5.0 mM for explant cells. Phenylbutyrate treatment reduced % S phase cells, increased % G0/G1 cells, and produced morphologic changes consistent with induction of differentiation. 24 hours of treatment with 4 mM phenylbutyrate resulted in a 50% reduction in migration and invasiveness. Northern blots showed a decrease in urokinase and c-myc expression at non-cytotoxic doses. We conclude that phenylbutyrate is a promising candidate compound for treating patients with malignant glioma.
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PMID:Inhibitory effects of phenylbutyrate on the proliferation, morphology, migration and invasiveness of malignant glioma cells. 952 87


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