Abstract:
:Cobalamin derivatives serve as coenzymes for the body's two cobalamin-dependent enzymes--adenosylcobalamin-dependent methylmalonyl CoA mutase, and methylcobalamin-dependent methionine methyltransferase. This essay reviews, in brief form and in personal terms, the history, beginning in the mid-1950s, of how these enzymes and coenzymes were discovered and what has been learned of their reaction mechanisms. It is clear that because of the fragility of the unique carbon-cobalt bond in cobalamin coenzymes, they serve primarily as free radical formers. This accounts for their efficiency in abstracting hydrogen from substrate molecules and for a subsequent chain of events that results in the isomerization of methylmalonyl CoA, the transfer of methyl groups, and (in certain bacteria) the reduction of ribonucleotides. Some thoughts are offered on the possible evolutionary significance of these facts.
journal_name
Am J Hematoljournal_title
American journal of hematologyauthors
Beck WSdoi
10.1002/ajh.2830340203subject
Has Abstractpub_date
1990-06-01 00:00:00pages
83-9issue
2eissn
0361-8609issn
1096-8652journal_volume
34pub_type
杂志文章,评审abstract::High-density lipoprotein (HDL) of 100-400 micrograms/ml did not prevent morphological alterations of human blood platelets treated with serotonin (1-5 microM). Highly concentrated HDL (1,200 micrograms/ml) appeared to activate platelets in vitro. These findings indicate that whole HDL may not inhibit agonist-induced p...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830500417
更新日期:1995-12-01 00:00:00
abstract::We report a family with a dominantly transmitted syndrome resembling Fanconi's anemia and spanning two generations. This syndrome was characterized by an ill-defined hematologic stem cell disorder, immune dysfunction, poor dentition, hyperpigmented skin, warts, and multiple second trimester spontaneous abortions and i...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830320402
更新日期:1989-12-01 00:00:00
abstract::Recombinant DNA technology and protein engineering are creating hope that we can address ongoing challenges in hemophilia care such as reducing the costs of therapy, increasing the availability to the developing world, and improving the functional properties of these proteins. Technological advances to improve the hal...
journal_title:American journal of hematology
pub_type: 杂志文章,评审
doi:10.1002/ajh.23146
更新日期:2012-05-01 00:00:00
abstract::Protein S (ProS) is a physiological inhibitor of coagulation with an important function in the down-regulation of thrombin generation. ProS deficiency is a major risk factor for venous thrombosis. This study enrolled 40 ProS-deficient probands to investigate the molecular basis of hereditary ProS deficiency in Chinese...
journal_title:American journal of hematology
pub_type: 临床试验,杂志文章,多中心研究
doi:10.1002/ajh.23525
更新日期:2013-10-01 00:00:00
abstract::The mechanism of multinucleated cell formation in Hodgkin's disease has not yet been elucidated. We asked whether the giant multinucleated cells of the H-RS cell line L1236 develop via fusion of the predominant smaller cells. As a positive control for the fusion assay, human B cells from the B-cell lymphoma cell line ...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.1068
更新日期:2001-05-01 00:00:00
abstract::Unprecedented advances in our understanding of the pathobiology, prognostication, and therapeutic options in mantle cell lymphoma (MCL) have taken place in the last few years. Heterogeneity in the clinical course of MCL-indolent vs aggressive-is further delineated by a correlation with the mutational status of the var...
journal_title:American journal of hematology
pub_type: 杂志文章,评审
doi:10.1002/ajh.25487
更新日期:2019-06-01 00:00:00
abstract::Lenalidomide and azacitidine are active in MDS patients, and may complement each other by targeting the bone marrow microenvironment and the malignant clone. A recent Phase I trial testing the lenalidomide and azacitidine combination yielded encouraging results; however, lenalidomide’s contribution was unclear. In thi...
journal_title:American journal of hematology
pub_type: 杂志文章,多中心研究
doi:10.1002/ajh.21891
更新日期:2011-01-01 00:00:00
abstract::A case of idiopathic immune-mediated von Willebrand's disease (AvWD) associated angiodysplasia and recurrent lower gastrointestinal bleeding is reported. Coagulation parameters at presentation were activated partial thromboplastin time of 41 sec, bleeding time >15 min, factor VIII procoagulant activity, 5%; von Willeb...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/(sici)1096-8652(199902)60:2<151::aid-ajh13
更新日期:1999-02-01 00:00:00
abstract::A patient with congenital protein-C deficiency was treated with stanozolol for 8 weeks to increase circulating levels of protein C. A rise in protein C was achieved, accompanied by an increase in factor II, factor X, antithrombin III, and protein S; but at the 8th week the patient suffered a transient ischemia attack....
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830290211
更新日期:1988-10-01 00:00:00
abstract::"Autonomous" development of erythroid colonies in erythropoietin (EPO)-free semi-solid culture has been used as an in vitro assay for diagnosis of polycythemia vera (PV). These colonies, however, are small and poorly hemoglobinized, rendering the assay in many cases unreliable. We report here on the use of a novel ass...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/(sici)1096-8652(199701)54:1<47::aid-ajh7>3
更新日期:1997-01-01 00:00:00
abstract::Hemoglobin Lyon-Bron was found in two members of a family of German ascent presenting with a moderate normocytic anemia. In this alpha 2 globin variant, the N-terminal valine of the chain was replaced by an alanine. Electrospray mass spectrometry of the alpha chain showed that, as normally, the initiator methionine wa...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.10051
更新日期:2002-03-01 00:00:00
abstract::Thrombotic complications occur at high rates in hospitalized patients with COVID-19, yet the impact of intensive antithrombotic therapy on mortality is uncertain. We examined in-hospital mortality with intermediate- compared to prophylactic-dose anticoagulation, and separately with in-hospital aspirin compared to no a...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.26102
更新日期:2021-01-21 00:00:00
abstract::The main treatment for many patients with Myelodysplastic Syndromes (MDS) remains red cell transfusion to attenuate the symptoms of chronic anemia. Fatigue can reduce a patient's health related quality of life (HRQoL), but there is little understanding of the optimal use of transfusions to improve this. A systematic r...
journal_title:American journal of hematology
pub_type: 杂志文章,评审
doi:10.1002/ajh.21503
更新日期:2009-10-01 00:00:00
abstract::A 68-year-old previously well woman developed sudden onset of limb gangrene in association with liver dysfunction. An immediately acting inhibitor to factor V with some of the features of lupus anticoagulant was demonstrated. The patient required limb amputation within 2 weeks and activity of the anticoagulant seemed ...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830420410
更新日期:1993-04-01 00:00:00
abstract::Over the past 40 years, public health measures such as universal newborn screening, penicillin prophylaxis, vaccinations, and hydroxyurea therapy have led to an impressive decline in sickle cell disease (SCD)-related childhood mortality and SCD-related morbidity in high-income countries. We remain cautiously optimisti...
journal_title:American journal of hematology
pub_type: 杂志文章,评审
doi:10.1002/ajh.24235
更新日期:2016-01-01 00:00:00
abstract::Seven normal human peripheral blood cell fractions (buffy coat, mononuclear cells, non-T, T, Fc-IgM receptor-depleted T-lymphocyte, Fc-IgG receptor-depleted T-lymphocyte, and autologous rosette-forming T-cell-depleted T-lymphocyte subpopulations) treated with phytohemagglutinin (PHA) were examined for the production o...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830200306
更新日期:1985-11-01 00:00:00
abstract::Some evidence has shown that platelet crossmatching is useful in multitransfused patients with hypoplastic bone marrows who are refractory to platelet therapy through alloimmunization. Several immunoglobulin binding assays other than enzyme-linked immunospecific assay (ELISA) have been studied previously. We performed...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830240407
更新日期:1987-04-01 00:00:00
abstract::How often elevated serum ferritin in primary-care patients reflects increased iron stores (normally 0.8 g in men, 0.4 g in women) is not known. The Hereditary Hemochromatosis and Iron Overload Screening (HEIRS) study screened 101,168 primary-care participants (44% Caucasians, 27% African-Americans, 14% Asians/Pacific ...
journal_title:American journal of hematology
pub_type: 杂志文章,多中心研究
doi:10.1002/ajh.21179
更新日期:2008-08-01 00:00:00
abstract::Defective fibrinolysis due to decreased tissue-type plasminogen activator (t-PA) activity is a well-established finding in patients with systemic lupus erythematosus (SLE). The possibility that this decrease in t-PA activity may be related to the presence of autoantibodies directed against t-PA, and the possible role ...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830490203
更新日期:1995-06-01 00:00:00
abstract::A risk score based on three biological features (CD38, ZAP-70, and IGHV mutational status) was previously developed to predict progression-free survival (PFS) in untreated Binet A CLL patients. Here we perform a score validation analysis in a prospective and independent cohort of patients. Biological markers (CD38, ZA...
journal_title:American journal of hematology
pub_type: 杂志文章,多中心研究
doi:10.1002/ajh.23729
更新日期:2014-07-01 00:00:00
abstract::The intravascular pool of human polymorphonuclear leukocytes (PMN) is composed of one compartment which is circulating and another that is marginated to the vascular endothelium. Administration of B-adrenergic agonists leads to a rapid demargination with an increase in the circulating PMN pool. The marginating PMN has...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830240107
更新日期:1987-01-01 00:00:00
abstract::The role of reduced-intensity conditioning (RIC) in adult acute lymphoblastic leukemia (ALL) remains unclear because of the small sample size, short follow-up duration, various regimens for conditioning and graft-versus-host disease (GVHD) prophylaxis, and the heterogeneity of selection criteria for transplantation. W...
journal_title:American journal of hematology
pub_type: 临床试验,杂志文章
doi:10.1002/ajh.23465
更新日期:2013-08-01 00:00:00
abstract::A 10-month-old infant with chronic myelomonocytic leukemia (CMML) of 5 months' duration, who had been treated only with transfusion, displayed leukemic transformation characterized by lymphoid morphology, PAS positivity, and myeloperoxidase negativity. Surface marker analysis of blast cells revealed expression of lymp...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/(SICI)1096-8652(199607)52:3<212::AID-AJH14
更新日期:1996-07-01 00:00:00
abstract::In this study, we analyzed a thiotepa-based conditioning regimen for allogeneic stem cell transplantation in adults with acute lymphoblastic leukemia, using the EBMT database. A total of 323 patients were identified. The median age was 43 years. Disease status at transplant was first complete remission (CR1) in 48.9%,...
journal_title:American journal of hematology
pub_type: 临床试验,杂志文章,多中心研究
doi:10.1002/ajh.24567
更新日期:2017-01-01 00:00:00
abstract::A 1750 base pair cDNA to human terminal deoxynucleotidyl transferase (TdT) has been cloned. This cDNA detects a dominant 2200 base pair messenger RNA species in normal and leukemic cells synthesizing the enzyme. A quantitative dot blot assay was utilized to survey a number of clinical samples from patients with TdT po...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830250305
更新日期:1987-07-01 00:00:00
abstract::Aplastic anemia is a disorder characterized by pancytopenia and bone marrow hypocellularity. There is some evidence that aplastic anemia may be due to suppression of hematopoiesis by activated T-suppressor cells. Thus, immunosuppressive agents have been used as an alternative to bone marrow transplantation for treatme...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/(SICI)1096-8652(199606)52:2<108::AID-AJH7>
更新日期:1996-06-01 00:00:00
abstract::Plasma cell dyscrasias are a group of clinically and biochemically diverse disorders of unknown etiology, characterized by the disproportionate proliferation of one or more clones of B cells, and the presence of a structurally and electrophoretically homogeneous (monoclonal) immunoglobulin or polypeptide subunit in se...
journal_title:American journal of hematology
pub_type: 杂志文章,评审
doi:10.1002/ajh.20736
更新日期:2006-12-01 00:00:00
abstract::We have developed a rapid approach to detect the two most common alpha-thalassemia-2 (alpha-thal-2) determinants by the polymerase chain reaction (PCR) technique, which takes a few hours to complete. Specific oligonucleotides selectively amplify appropriate segments of the chromosome with the deletion and the normal c...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.2830460309
更新日期:1994-07-01 00:00:00
abstract::A 28-year-old asymptomatic male of Iranian Jewish (Meshadi) heritage was found on routine exam to have an erythrocytosis (RBC = 6.22 x 10(12)/l, Hgb = 19.2 g/dl, Hct = 58.9%). Splenomegaly was absent on physical exam. There was no family history of erythrocytosis. His oxygen dissociation curve was left-shifted with a ...
journal_title:American journal of hematology
pub_type: 杂志文章
doi:10.1002/ajh.20014
更新日期:2004-04-01 00:00:00
abstract:DISEASE OVERVIEW:Cutaneous T-cell lymphomas are a heterogenous group of T-cell lymphoproliferative disorders involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS). DIAGNOSIS:The diagnosis of MF or SS requires the integration of clinical and histopathologic data. ...
journal_title:American journal of hematology
pub_type: 杂志文章,评审
doi:10.1002/ajh.23756
更新日期:2014-08-01 00:00:00