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

A somewhat simplified modification of a previously described method for the measurement of red cell membrane phosphorylation by ATP has been devised. Phosphorylation of membranes was linear with time for only 5-10 min, and linearity with membrane concentration was observed only when assays were limited to short incubation times. Protein kinase activity of hereditary spherocytosis (HS) membranes was found to be normal. However, the average phosphorylation after 60 min incubation was less in HS membranes than in normal membranes. Findings similar to those in HS membranes were observed in sickle cell disease. The Km of red cell protein kinase for ATP is approximately 10(-5) M. Membrane phosphate binding sites are not saturated in either HS or normal membranes after 1 hr incubation with ATP. Approximately 27% of phosphorylating activity is lost after 1 hr incubation at 37 degrees C. GTP is a very inefficient phosphate donor. Under the conditions of measurement employed, the enzyme is slightly stimulated by 1 muM cAMP, but is not stimulated by 1 muM cGMP. Dephosphorylation of red cell membranes after labeling occurs at a similar rate in HS as in normal membranes. Although a mild abnormally in membrane phosphorylation is observed in HS, this could not be demonstrated to be due to a decrease in protein kinase activity or in alterations of its kinetic properties. The abnormally seen is not specific for HS.
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PMID:Human red cells protein kinase in normal subjects and patients with hereditary spherocytosis, sickle cell disease, and autoimmune hemolytic anemia. 18 65

In the rabbit, a p59 protein included in the untransformed, non-DNA binding, "8-9S," steroid receptor complexes binds heat shock protein M(r) approximately 90,000 (hsp90). Sequence data [Lebeau, M. C., Massol, N., Herrick, J., Faber, L. E., Renoir, J. M., Radanyi, C. & Baulieu, E. E. (1992) J. Biol. Chem. 267, 4281-4284] and hydrophobic cluster analysis delineate, from the N terminus, two successive domains closely related to the immunosuppressant FK506 binding immunophilin FKBP (FK506 binding protein), consistent with recent purification of the human p56 immunophilin cognate protein by FK506 affinity chromatography [Yem, A. W., Tomasselli, A. G., Heinrikson, R. L., Zurcher-Neely, H., Ruff, V. A., Johnson, R. A. & Deibel, M. R., Jr. (1992) J. Biol. Chem. 267, 2868-2871]. The first FKBP-like domain demonstrates all structural characteristics known to be necessary for immunosuppressant binding and for peptidylprolyl cis-trans isomerase (rotamase) activity. Hence, p59 is a "hsp binding immunophilin" (HBI). It is thus speculated that hsp binding immunophilin may help the assembly/disassembly mechanisms involved in steroid receptor trafficking and activity and participate in the poorly understood hsp90 function. ATP/GTP binding likely occurs within the second FKBP-like domain, near the FK506 binding site on the FKBP template. A third domain detected by the hydrophobic cluster analysis method is distantly structurally related to the two first FKBP-like domains and is followed by the C-terminal part of the protein, which contains a calmodulin binding consensus sequence. Hsp binding immunophilin may be involved in a number of immunological, endocrinological, and chaperone-mediated pathways.
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PMID:An immunophilin that binds M(r) 90,000 heat shock protein: main structural features of a mammalian p59 protein. 163 Nov 18

Sickle-cell anemia results from an A leads to T transversion in the second nucleotide of codon 6 of the beta-globin gene. We now report an uncommon beta-thalassemia gene that contains a deletion of this nucleotide. Thus, one mutation (GAG leads to GTG) produces sickle-cell anemia, while the other (GAG leads to GG) eliminates beta-globin production. These data establish that different alterations affecting one specific nucleotide can produce either an abnormal hemoglobin or beta-thalassemia. Moreover, the nucleotide sequence comprising codons 6-8 of the beta-globin gene appears to be particularly susceptible to mutations affecting nucleotide number.
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PMID:beta-Thalassemia due to a deletion of the nucleotide which is substituted in the beta S-globin gene. 631 Sep 91

A new T --> A base substitution, identified inside the 5' regulatory region of the human Agamma globin gene (Agamma-499 T -->A), is reported. This nucleotide change was found to be linked in cis with the mutation producing sickle cell anemia (CD6 GAG-->GTG: betaS gene).
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PMID:A new base substitution in the 5' regulatory region of the human Agamma globin gene is linked with the betaS gene. 878 81

Sickle hemoglobin (Hb S; beta Glu6Val) is due to an A<T transversion in codon 6 of the beta-globin gene. Several Hb S variants have both the Hb S mutation plus another mutation in the same beta-globin gene. Some of these variant hemoglobins can lead to sickle cell disease even in the simple heterozygote. Moreover, some variant hemoglobins mimic Hb A, S, or C on one or several clinical laboratory diagnostic tools, thus making their correct identification potentially problematic. The authors report a novel Hb S variant hemoglobin, Hb S-South End (beta Glu6Val, GAG>GTG; beta Lys132Asn, AAA>AAC). When present alone, the beta Lys132Asn mutation has low oxygen affinity. Therefore, this mutation may enhance the polymerization of the Hb S variant. Furthermore, the variant hemoglobin mimics Hb A on high-pressure liquid chromatography, and its identity is not easily diagnosed. A succinct review of variant sickle hemoglobins is also presented.
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PMID:A novel sickle hemoglobin: hemoglobin S-south end. 1554 18

Vaso-occlusion is a hallmark of sickle cell disease. Agonist-induced activation of sickle red blood cells (SS RBCs) promotes their adhesion to vascular proteins, potentially contributing to vasoocclusion. Previously, we described a cyclic adenosine monophosphate (cAMP)-dependent increase in SS RBC adhesion to laminin. Here, we investigated whether Rap1, a small guanosine triphosphatase (GTPase) known to promote integrin-mediated adhesion in other cells, was involved in this signaling pathway. We found that agonists known to induce cAMP signaling promoted the GTP-bound, active state of Rap1 in SS RBCs. The cAMP-dependent exchange factor Epac (exchange protein directly activated by cAMP) is a likely upstream activator of Rap1, since Epac is present in these cells and the Epac-specific cAMP analog 8CPT-2-Me (8-(4-cholorophenylthio)-2'-O-methyl-cAMP) activated Rap1 and promoted SS RBC adhesion to laminin. This 8CPT-2-Me-stimulated adhesion was integrin independent, since it was insensitive to RGD peptide or antibodies against the only known integrin on SS RBCs, alpha4beta1. However, this adhesion was completely inhibited by either a soluble version of basal cell adhesion molecule/Lutheran (BCAM/LU) or a BCAM/LU adhesion-blocking anti-body. Surprisingly, 8CPT-2-Me-activated Rap1 did not promote SS RBC adhesion to a known alpha4beta1 ligand, vascular cell adhesion molecule 1 (VCAM-1). These results demonstrate that Epac-induced Rap1 activation in SS RBCs promotes BCAM/LU-mediated adhesion to laminin. Thus, Epac-mediated Rap1 activation may represent an important signaling pathway for promoting SS RBC adhesion.
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PMID:Role of Rap1 in promoting sickle red blood cell adhesion to laminin via BCAM/LU. 1561 46

The determination of the prevalence of inherited hemoglobin (Hb) disorders in endemic areas is important in order to develop programs for their control and management. The aim of this study is to determine the prevalence of inherited Hb diseases in Guinea-Bissau which is situated on the west coast of Africa, between Senegal and Guinea. One thousand and fifty-seven blood samples were collected and analyzed with high performance liquid chromatography (HPLC) for detection of beta-thalassemia (thal) and Hb variants, and by gap polymerase chain reaction (gap-PCR) for the detection of deletions in the alpha-globin genes. We found 4.7% children were heterozygous for Hb S [beta6(A3)Glu-->Val, GAG -->GTG], 0.2% were homozygous for Hb S, and 0.3% were heterozygous for Hb C [beta6(A3)Glu-->Lys, GAG -->AAG]. One child had heterozygous beta+-thal, 13.8% were heterozygous for the -alpha3.7 deletion, 1.5% were homozygous for the -alpha3.7 deletion, and 1.5% were heterozygous for the -alpha4.2 deletion. We recommend national screening programs to focus primarily on sickle cell disease, since beta-thal is rare, and the observed alpha-thal deletions are of minor genetic importance.
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PMID:Inherited hemoglobin disorders in Guinea-Bissau, West Africa: a population study. 1684 Feb 26

Hemolysis, long discounted as a critical measure of sickle cell disease severity when compared with sickle vaso-occlusion, may be the proximate cause of some disease complications. New mechanistic information about hemolysis and its effects on nitric oxide (NO) biology and further examination of the subphenotypes of disease requires a reappraisal and deconstruction of the clinical features of sickle cell disease. The biology underlying clinical phenotypes linked to hemolysis may increase our understanding of the pathogenesis of other chronic hemolytic diseases while providing new insights into treating sickle cell disease. The pathophysiological roles of dysregulated NO homeostasis and sickle reticulocyte adherence have linked hemolysis and hemolytic rate to sickle vasculopathy. Nitric oxide binds soluble guanylate cyclase which converts GTP to cGMP, relaxing vascular smooth muscle and causing vasodilatation. When plasma hemoglobin liberated from intravascularly hemolyzed sickle erythrocytes consumes NO, the normal balance of vasoconstriction:vasodilation is skewed toward vasoconstriction. Pulmonary hypertension, priapism, leg ulceration and stroke, all subphenotypes of sickle cell disease, can be linked to the intensity of hemolysis. Hemolysis plays less of a role in the vaso-occlusive-viscosity complications of disease like the acute painful episode, osteonecrosis of bone and the acute chest syndrome. Agents that decrease hemolysis or restore NO bioavailability or responsiveness may have potential to reduce the incidence and severity of the hemolytic subphenotypes of sickle cell disease. Some of these drugs are now being studied in clinical trials.
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PMID:Deconstructing sickle cell disease: reappraisal of the role of hemolysis in the development of clinical subphenotypes. 1708 51

A 38-year-old Ghanaian man presented with a 6-month history of worsening pruritus, jaundice, and ascites. He was previously fit and well and rarely drank alcohol. Screening tests for chronic liver disease including viral, autoimmune, and other metabolic causes including iron overload were unremarkable. A liver biopsy performed at the referring hospital demonstrated intralobular cholestasis and cirrhosis. He was listed for liver transplantation but subsequently developed sepsis with multiple organ failure and died. The sickle solubility test was positive. Blood smear showed cells consistent with liver failure and no sickle cells. Hemoglobin electrophoresis revealed HbA2 2.8%, HbF 0.5%, and HbS greater than HbA (49.6% vs. 41.3%) in the absence of blood transfusion. Sequence analysis of the beta-globin genes showed he was a compound heterozygote for the Hbs mutation at codon 6 (CAG --> GTG) and a novel mutation at position 844 of intron 2 (betaIVS2-844 C --> A). A diagnosis of sickle hepatopathy causing decompensated cirrhosis was made. This case is unusual insomuch as this patient was asymptomatic for over 35 years and represents a novel presentation of sickle cell disease. Sickle cell disease should be considered in appropriate patients when unusual presentations of liver disease arise.
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PMID:Sickle liver disease--an unusual presentation in a compound heterozygote for HbS and a novel beta-thalassemia mutation. 1756 24

Hemoglobinopathies are the most common genetic diseases in Turkey. The incidence of sickle cell trait is 10.0% and beta-thalassemia (beta-thal) trait is 3.7% in the Cukurova region of southern Turkey. Sickle cell anemia is prevalent in the Cukurova region, but beta-thal is seen all over the country. A prenatal diagnosis center was established in 1992 at Adana, Turkey, for the prevention of sickle cell anemia and beta-thal. Fifteen hundred and seventy-five fetuses were examined at the Cukurova University Hospital, Adana, Turkey. Three hundred and eighty-six fetuses were diagnosed as homozygous or compound heterozygous for sickle cell anemia and beta-thal. A total of 15 different beta-thal mutations were characterized in the parents. The incidence of the IVS-I-110 (G > A) mutation accounted for about 50.0% of the parents with beta-thal trait. Twenty-four different genotypes were observed in this study. A total of 286 fetuses were diagnosed with homozygous sickle cell disease, 57 fetuses were beta-thal homozygotes, 25 fetuses were compound heterozygotes with Hb S [beta6(A3)Glu-->Val, GAG > GTG], and 18 of the fetuses were double heterozygotes for beta-thal mutations.
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PMID:Prenatal diagnosis of sickle cell anemia and beta-thalassemia in southern Turkey. 1906 29


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