Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002895 (sickle cell disease)
 11,747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used a new method of DNA analysis for the rapid prenatal diagnosis of sickle cell anemia in two fetuses at risk for this disease. This method of detecting the sickle gene is a modification of standard restriction-enzyme techniques and requires only a small amount of DNA. The first step involves a 200,000-fold enzymatic amplification of the specific beta-globin DNA sequences that may carry the sickle mutation. This provides a sufficient quantity of DNA for the analysis. Next, a short radiolabeled synthetic DNA sequence homologous to normal beta A-globin gene sequences is hybridized to the amplified target sequences. The hybrid "duplexes" are then digested sequentially with two restriction endonucleases. The presence of beta A- or beta S-globin gene sequences in the amplified target DNA from the patient determines whether the beta A-hybridization probe anneals perfectly or with a single nucleotide mismatch. This difference affects the restriction-enzyme digestion of the DNA and the size of the resulting radiolabeled digestion products, which can be distinguished by electrophoresis followed by autoradiography. This method is sufficiently sensitive and rapid that the prenatal diagnosis of sickle cell anemia can be made on the same day that the fetal DNA is made available. It can also be applied to the diagnosis of hemoglobin C disease.
 ...
PMID:Rapid prenatal diagnosis of sickle cell anemia by a new method of DNA analysis. 382 96

Genetic and biochemical evidence indicates that in beta-thalassemia there is impaired synthesis of the beta-globin chains of hemoglobin A. In patients heterozygous for the hemoglobinopathies, hemoglobin S and hemoglobin C, the mutant beta-chain is produced in smaller amounts than normal beta(A). Defective m-RNA translation has been suggested as a possible cause of decreased beta-globin polypeptide synthesis in thalassemia and the hemoglobinopathies. In the present study, the ribosomal assembly of beta-globin chains was examined in the peripheral, nucleated red blood cells and reticulocytes of patients with Cooley's anemia, thalassemia intermedia, sickle thalassemia, sickle cell anemia, hemoglobin C disease, and in hemolytic anemias not associated with a hemoglobinopathy. The translation times of beta(A), beta(S), and beta(C) did not differ significantly (average times; beta(A) = 75 sec, range 43-114, beta(S) = 69 sec, beta(C) = 92 sec). In thalassemia, no evidence was found for a delay in translation as the cause of the marked impairment of beta-globin synthesis. In several specimens of peripheral blood from thalassemic patients, the translation time of the beta-chain was even shorter than in nonthalassemic specimens (average time = 45 sec, range 35-59). The results suggest that the defect in beta-globin synthesis in beta-thalassemia is due to impaired initiation of beta-globin chain assembly or a quantitative deficiency in m-RNA.
 ...
PMID:Translation of -globin m-RNA in -thalassemia and the S and C hemoglobinopathies. 500 20

Human hemoglobin messenger RNA was isolated by sucrose gradient centrifugation from reticulocytes of patients having various hemolytic anemias. Using a messenger RNA-dependent cell-free system derived entirely from rabbit reticulocytes, the human hemoglobin messenger RNA has been translated and the products analyzed by carboxymethylcellulose column chromatography. Normal messenger RNA directs synthesis of normal human alpha- and beta-globin chains in nearly equal amounts. Sickle cell anemia messenger RNA directs the synthesis of normal alpha- and sickle beta-chains, beta-thalassemia messenger RNA directs the synthesis of normal alpha- and beta-chains, but the amount of beta-globin synthesized is markedly reduced. Thus the inability of the thalassemia reticulocyte to produce beta-globin is clearly attributable to the beta-globin messenger RNA.
 ...
PMID:Isolation and translation of hemoglobin messenger RNA from thalassemia, sickle cell anemia, and normal human reticulocytes. 509 28

Sickle cell anemia was detected antenatally by restriction analysis with the enzyme Dde I, which cleaves normal human DNA at the position corresponding to aminoacid number 6 of the beta-globin chain. This site is abolished by the mutation in sickle cell disease, and hence different-sized fragments are generated on digestion of normal and sickle genes with this enzyme. In a pregnancy at risk for sickle cell anaemia, digestion of DNA from cultured amniotic fluid cells revealed a pattern indicating the haemoglobin AA genotype. The diagnosis was later confirmed by fetal blood analysis. The test proved applicable to the sickle gene from Africa, Asia, The Middle East, and two Mediterranean countries.
 ...
PMID:Antenatal diagnosis of sickle cell anaemia by direct analysis of the sickle mutation. 611 75

We previously demonstrated that 5-azacytidine can selectively increase gamma-globin synthesis in a patient with beta +-thalassemia, prompting us to treat two patients with sickle cell anemia and two additional patients with beta + thalassemia. 5-Azacytidine (2 mg/kg/day) was continuously infused for 7 days with no apparent clinical toxicity. The gamma/beta-globin biosynthetic ratio increased fourfold to sixfold in the bone marrow cells of each patient after treatment and remained elevated for 7-14 additional days. Hypomethylation of DNA near the gamma-globin genes in bone marrow cells was demonstrated 2 days after beginning the 5-azacytidine infusion. The peripheral blood fetal hemoglobin (HbF) level increased from 6.0% to 13.7% in one patient with sickle cell anemia and from 1.6% to 8.9% in the second. Stractan gradient analyses of peripheral blood from patients with sickle cell anemia revealed a marked decrease in the percentage of dense cells (cells that contain increased amounts of HbS polymer when deoxygenated) following treatment. These observations provide an impetus to investigate the effects of repeated courses of 5-azacytidine in a small group of severely ill patients to determine whether this drug may have a role in the treatment of patients with sickle cell anemia and beta-thalassemia.
 ...
PMID:5-Azacytidine increases gamma-globin synthesis and reduces the proportion of dense cells in patients with sickle cell anemia. 619 99

Increased production of fetal hemoglobin (HbF) was observed in a patient with sickle cell anemia treated with 5-azacytidine. Each of four courses of therapy resulted in a rapid and prolonged increase in the percentage of HbF containing reticulocytes (F reticulocytes) and HbF containing erythrocytes (F cells). The percentage of HbF in peripheral blood rose from 1.8 to 8.9%. The rise in HbF production was accompanied by an increase in peripheral blood hemoglobin concentration from 8 to 12 g/dl and an increase in mean erythrocyte volume. Treatment with 5-azacytidine resulted in hypomethylation of total genomic and a Y-chromosome-specific DNA fragment isolated from both peripheral blood and bone marrow. Of 15 restriction enzyme sites around the gamma-delta-beta-globin gene complex, only 2 became hypomethylated: one 107 bases 5' to the gamma G and the other 107 bases 5' to the gamma A globin genes.
 ...
PMID:Treatment of sickle cell anemia with 5-azacytidine results in increased fetal hemoglobin production and is associated with nonrandom hypomethylation of DNA around the gamma-delta-beta-globin gene complex. 619 43

Several reports have been published on the use of polymorphisms found in the human hemoglobin genes as a means for prenatal diagnosis of sickle cell anemia. The disadvantages of this approach reside in its limited application and the need for family analysis. Here we report that, by use of restriction endonuclease Dde I and diazobenzyloxymethyl-paper transfer procedures, a direct analysis can be made. Individuals with normal hemoglobin (AA) show two bands (175 and 201 base pairs) complementary to a 5'-specific beta-globin gene probe. Sickle cell trait individuals (AS) exhibit an additional band (376 base pairs). Individuals with sickle cell anemia (SS) show the band at 376 base pairs with a concomitant loss of the 175-base pair band. We interpret these changes in banding pattern to be the result of the elimination of a restriction site for Dde I in the altered codon associated with the sickle cell allele. Because an analysis can be performed on as little as 20 micrograms of cellular DNA, the application to prenatal diagnosis of sickle cell anemia should be possible.
 ...
PMID:Direct identification of sickle cell anemia by blot hybridization. 627 89

Prenatal diagnosis by amniocentesis alone is possible for about 90% of pregnancies at risk for sickle cell anemia and about 70-75% of pregnancies at risk for beta-thalassemia. It should be stressed that to obtain these percentages, a previous homozygous normal or affected child or, alternatively, the couple's parents are needed to confirm the linkage of variant genes to respective DNA markers (polymorphic restriction sites). Families at risk should be studied prior to or early in pregnancy to determine whether these methods will be applicable to their specific case. If appropriate markers are identified and their linkage to the genes being studied is verified, then prenatal diagnosis by amniocentesis can be done at 16-18 weeks; and for these couples, fetoscopy, with its increased risk of fetal loss, can be avoided. The change of errors in diagnosis due to crossing-over between the mutant gene and the linked marker is small. The probability of such a recombination between the beta-globin gene and the polymorphic G gamma Hind III or the 3' Hpa I site is 1/3,000 and 1/14,000 per generation, respectively (13). A more serious problem is non-paternity because of the errors caused in linkage analysis. Improved methods to enable direct detection of the beta S and/or beta thal mutations would remove both of these potential sources of error.
 ...
PMID:Prenatal diagnosis of sickle cell anemia and beta-thalassemia by amniocentesis. 627 66

We have reported the direct analysis of the allele for beta 2-globin by using restriction endonuclease Dde I coupled with blot-hybridization analysis. In that report we predicted that a major use of our analysis could be for the prenatal diagnosis of sickle cell anemia. Here we present such an analysis. In addition, this report also describes the use of a new enzyme Mst II, which also distinguish the beta s allele from the normal beta-globin allele. Blot-hybridization analysis with restriction endonuclease Mst II shows the 5' end of the normal beta-globin gene to reside on a fragment of approximately 1.14 kilobases, whereas the 5' end of the beta s-globin gene resides on a fragment of approximately 1.34 kilobases. Because the fragment sizes generated by Mst II are significantly larger than those generated by Dde I, one can easily perform a prenatal diagnosis for sickle cell by standard blot hybridizations onto nitrocellulose filters.
 ...
PMID:Use of restriction endonucleases for mapping the allele for beta s-globin. 628 54

The restriction endonuclease MstII cleaves the human beta-globin gene at the position corresponding to amino acids 5, 6, and 7. The beta S mutation at this position abolishes the recognition site. Hence, the two normal DNA fragments in this region, 1.15 and 0.2 kb in length, are replaced by a single 1.35-kb fragment in DNA from sickle cell anemia. We have set up an assay using these findings. The assay is extremely sensitive and can be applied to DNA directly harvested from 20 ml of amniotic fluid.
 ...
PMID:A sensitive test for prenatal diagnosis of sickle cell anemia: direct analysis of amniocyte DNA with MstII. 630 79


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>