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F Galacteros

Publications and source records attributed to F Galacteros.

At least 37 records · Page 2Linked to original sources
PubMed1996

Perfusion chromatography on reversed-phase column allows fast analysis of human globin chains.

Human globin chain analysis provides important information on the genetics and molecular pathophysiology of hemoglobinopathies. We propose using perfusion chromatography on the reversed-phase stationary phase to perform these studies. The technique, herein described, involves a high-velocity flow of the mobile phase through a porous chromatographic stationary phase made of microspheres of poly(styrene-divinylbenzene) having throughpores of 6000-8000 A diameter with short diffusive pores of 500-1000 A diameter connected to them. The composition of fetal hemoglobin (Ggamma:Agamma ratio) is determined, using this method, as an order of magnitude faster than with conventional HPLC. Elution is performed by developing a linear gradient of acetonitrile at a flow rate of 3 ml/min (or more), easily obtained on any HPLC machine. Analyses may be done on samples containing as low as 3.0% Hb F. Results are similar to those obtained with the reference HPLC technique, which uses a C4 column. In addition, reversed-phase perfusion chromatography, using a shallow curvilinear gradient, may help in the characterization of Hb variants. This technique allowed us to discriminate several alpha and beta chain mutants from variants that have closely similar patterns of electrophoretic mobilities.

Chromatography↗
PubMed1996

Priapism following splenectomy in an unstable hemoglobin: hemoglobin Olmsted beta 141 (H19) Leu-->Arg.

We report a case of severe priapism occurring in a patient with an unstable hemoglobin, Hb Olmsted (beta 141 Leu-->Arg) This is a rare hemoglobin variant, which until now has been reported only once. The clinical course of the 12-year-old boy was characterized by severe hemolytic anemia leading to splenectomy and cholecystectomy at the of 3.5 years. The priapism occurred 8 years after splenectomy, during a hemolytic febrile episode and required aspiration of the corpora cavernosa. This report raises the question of the benefit of splenectomy in patients suffering from a chronic hemolytic anemia such as that due to an unstable hemoglobin. This treatment lowers the frequency and the severity of acute hemolytic attacks, but several cases of vascular complications have been reported after splenectomy.

Anemia, Hemolytic↗
PubMed1996

Preventive treatment of priapism in sickle cell disease with oral and self-administered intracavernous injection of etilefrine.

OBJECTIVES: Priapism is a common and currently unsatisfactorily managed complication of sickle cell disease (SCD). In June 1994, 6 SCD patients received a new therapeutic regimen to prevent the occurrence and recurrence of priapism. METHODS: The patients (5 with SS and 1 with SC) were adults and had frequent episodes of stuttering priapism (SP), and two of them had had acute episodes (AP) lasting more than 3 hours. The treatment consists of preventive oral administration of the alpha-adrenergic agent etilefrine, and self-administered intracavernous injection (SICI) of the same agent to reverse episodes lasting more than 1 hour. RESULTS: Since the beginning of treatment, all patients were protected against AP, 4 patients had no recurrence with the oral treatment alone, 2 had to use SICI, 1 occasionally and 1 constantly. There was no modification of sexual activity and no complications. Blood pressure was unaffected. CONCLUSIONS: This treatment is simple, cheap, and self-administered. It should be proposed to all patients with SCD in all geographic areas as part of an educational program for active prevention of this severe complication.

Administration, Oral↗
PubMed1996

Bronchoalveolar lavage in adult sickle cell patients with acute chest syndrome: value for diagnostic assessment of fat embolism.

Fat embolism of necrotic bone marrow could be a frequent cause of acute chest syndrome (ACS) in sickle cell syndromes (SC), as suggested by postmortem findings. To check this hypothesis in living patients, we evaluated the presence of fatty macrophages recovered by bronchoalveolar lavage (BAL) in ACS. We investigated 20 consecutive cases of ACS by BAL, and identification of alveolar cells containing fat droplets was performed using oil red O (ORO), a specific neutral fat stain. The specificity of the method was determined on control groups, including eight SC patients without acute chest syndrome and 15 non-SC patients. A cut-off of > 5% of alveolar macrophages containing fat droplets was determined from the control groups to assess the diagnosis of fat embolism. In 12 ACS episodes, BAL exhibited > 5% of fatty macrophages, ranging from 10% to 100% (median value 46.5%). In 11 cases, fat embolism was associated with proven (n = 8) or probable (n = 3) bone marrow infraction, which mostly predated ACS. Eight ACS episodes were associated with a low percentage (< or = 5%) of fatty alveolar macrophages and could be related to a cause other than fat embolism in six episodes, such as sepsis, in-situ thrombosis, or rib infarcts generating hypoventilation. This study supports the diagnostic yield of BAL for fat embolism, which can be incriminated in 60% of cases of ACS in this adult population.

Adolescent↗
PubMed1996

A novel mutation in the putative DNA helicase XH2 is responsible for male-to-female sex reversal associated with an atypical form of the ATR-X syndrome.

We describe a pedigree presenting X-linked severe mental retardation associated with multiple congenital abnormalities and 46,XY gonadal dysgenesis, leading in one family member to female gender assignment. Female carriers are unaffected. The dysmorphic features are similar to those described in the alpha-thalassemia and mental retardation (ATR-X) syndrome, although there is no clinical evidence of alpha-thalassemia in this family. In addition, the family had other clinical features not previously observed in the ATR-X syndrome, including partial optic-nerve atrophy and partial ocular albinism. Mutations in a putative DNA helicase, termed XH2, have been reported to give rise to the ATR-X syndrome. We screened the XH2 gene for mutations in affected members of the family and identified a 4-bp deletion at an intron/exon boundary that removes an invariant 3' splice-acceptor site. The mutation cosegregates with the syndrome. The genomic deletion causes missplicing of the pre-mRNA, which results in the loss of 8 bp of coding sequence, thereby generating a frameshift and a downstream premature stop codon. Our finding increases the range of clinical features associated with mutations in the XH2 gene.

Abnormalities, Multiple↗
PubMed1996

Implications of prenatal diagnosis of sickle cell disease.

Prenatal diagnosis (PND) of sickle cell disease (SCD) has been feasible since about 15 years. The number of PND performed for SCD has constantly increased during these years, but its availability raises difficult ethical questions for parents and counsellors. Concerning at-risk parents, only 50% (data in the literature) to 70% (personal data) ask for PND. Our study shows that mainly cultural reasons, then religious ones, educational level and the number of children in the family weigh on the parents' decision to request this diagnosis. The counsellors' position is difficult since clinical severity of the disease is highly variable, there is no early prognostic factor, and the median life expectancy of patients in industrialized countries exceeds 40 years. We need to define a counselling which would consider the image of the illness in the populations involved, in order to help parents understand the implications of the choice they are asked to make.

Abortion, Eugenic↗
PubMed1995

[Prenatal diagnosis of homozygous pyruvate kinase deficiency].

Two consecutive cases of severe neonatal anaemia due to severe deficiency in pyruvate kinase were observed in the same sibhood. The first child died one hour after birth and the second required major transfusion support. Pyruvate kinase deficiency is a rare cause of congenital anaemia with recessive autosomic inheritance. Clinically, this deficiency has a very variable expression, and neonatal forms are not always very severe. Several variant molecules in pyruvate kinase deficiency have been described. Recent progress in our understanding of the gene would suggest the possibility of new diagnostic and prognostic approaches.

Anemia, Hemolytic, Congenital↗
PubMed1995

Structural determination of a new electrophoreticaly silent variant: hemoglobin Alzette, beta 104(G6)Arg --> Lys.

A new electrophoreticaly neutral hemoglobin variant was found by ion-exchange high-performance liquid chromatography (HPLC). The molecular mass of the beta-chain was shifted down 28 mass units. The modification was found in the beta T-11 peptide that co-elutes with beta T-14 in the tryptic HPLC profile. Collision-induced decomposition of the protonated modified peptide indicated the Arg --> Lys exchange at the C-terminus. This modifies the fragmentation pattern as charge-remote processes induced by the strong basicity of arginine were replaced by charge-induced mechanisms. The exchanged 104Arg is one of the chloride binding sites in the central cavity of Hb.

Amino Acid Sequence↗
PubMed1994

The involvement of the Ca-dependent K channel and of the KCl co-transport in sickle cell dehydration during cyclic deoxygenation.

We have investigated the mechanisms involved in sickle cell dehydration upon continuous or cyclic deoxygenation: the Ca(2+)-activated K+ channel and the KCl co-transport system. Short-term continuous deoxygenation (1 h) of sickle cells in a Ca(2+)-containing medium promoted a stimulation of the efflux of K+ and cell dehydration. This latter was reduced by the replacement of Ca2+ in the medium by EGTA, but not by addition of [(dihydro-indenyl) oxy] alkanoic acid (DIOA), an inhibitor of the KCl co-transport. During cycles of deoxygenation-reoxygenation, cell dehydration was partly prevented by EGTA and significantly reduced by DIOA only in the presence of Ca2+. The present data support the view that sickle cell dehydration during deoxygenation arises from the stimulation of the Ca(2+)-dependent K+ permeability leading to water loss, whereas during reoxygenation periods, subsequent activation of the KCl co-transport also contributes to cell dehydration.

Anemia, Sickle Cell↗
PubMed1994

Hb Cemenelum [alpha 92 (FG4) Arg-->Trp]: a hemoglobin variant of the alpha 1/beta 2 interface that displays a moderate increase in oxygen affinity.

Hb Cemenelum [alpha 92 (FG4) Arg-->Trp] carries a structural modification at the same position as Hb Chesapeake, a very high oxygen affinity variant. Hb Cemenelum was found in a French diabetic patient with no abnormal hematological features. The purified abnormal hemoglobin, like Hb J Cape Town, another variant of position alpha 92(FG4), displayed only a 1.5- to 2-fold increased oxygen affinity and a reduced cooperativity. This hemoglobin demonstrates that, even for some key residues of the alpha 1/beta 2 interface, the degree at which the functional properties are altered depends upon the specific residue occupying this position.

Amino Acid Sequence↗
PubMed1994

[Extensive bone marrow necrosis and major sickle cell syndromes].

Three cases of extensive bone marrow necrosis in patients with sickle cell disease are reported. All three patients presented severe bone pains with severe anaemia (haemoglobin value less than 5 g/dl) and high increased of LDH serum values (upper than 20 fold normal value). Bone marrow aspirate and biopsy showed typical signs of necrosis. The extent of necrosis was evaluated by reticuloendothelial scan obtained with 111In chloride. Treatment required transfusions of phenotyped red blood cell concentrates. Favourable outcome was observed in all patients.

Adult↗
PubMed1994

[Transfusion and alloimmunization in sickle cell anemia patients].

Transfusion therapy for sickle cell anemia is limited by the development of antibodies to red cell antigens. The aim of this study was to evaluate whether transfusion of blood matched for antigens Rh and Kell would reduce the incidence of alloimmunization. We determined the transfusion history, red cell phenotype and development of alloantibodies in 173 patients with sickle all anemia who received transfusions. Forty nine patients were transfused exclusively with frozen red blood cells (RBL) matched for antigens Rh and Kell; the rate of alloimmunization was 8.2%; antibodies to the Jkb, Jka, Fya and S were developed; 1 patient developed 2 antibodies. In a control group of 124 patients who received standard red blood cells, the rate of alloimmunization was significantly increased to 30.6% (p < 0.05); antibodies against C, E, K, Fya were the most frequently developed and 19 patients (16%) developed antibodies reacting with different antigens. In the 2 groups, alloimmunization occurred after receiving a significantly different number of transfusions: mean 9 in the patients transfused with matched RBC and 32 in the control group. The influence of the kinetics of transfusion was not demonstrated. To assess the effect that racial differences might have on alloimmunization, comparison of the red cell phenotype of patients with that of a panel of unselected blood bank donors was performed: the patients had a significant decrease in the frequency of red cell antigens corresponding to most of the detected alloantibodies JkB, C, S. Fyb, Fya and Kell.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Potential alternatives to erythrocyte transfusion in hemoglobinopathies: hydroxyurea (HU), erythropoietin (EPO), butyrate derivatives, blood substitutes].

Transfusion is associated with improvement of life expectancy in beta thalassemia and sickle cell disease (SCD). Bone marrow transplantation concerns only a few patients. Among potentially useful therapeutic agents which can induce fetal hemoglobin (HbF) production, hydroxyurea (HU) stands out in particular for SCD. In our sickle cell center, 10 patients with SCD received HU for chronic leg ulcer with good results in terms of healing (7 among 10, who required no additional transfusion). A few patients, most of them over 30 years, received HU for chronic organ failure at the onset. HU on long term therapy over one year improved general status, Hb level, in 7 patients with beta thalassemia intermedia. A major challenge in the coming years will be the effective evaluation of clinical efficiency and the comparison of risks and benefits of such compounds versus transfusion.

Adolescent↗
PubMed1994

The use of Staphylococcus V8 protease in the structural determination of human hemoglobin variants: HB Valparaiso [alpha 88(F9)Ala-->Gly] example.

In human hemoglobin, enzymic cleavage with the protease from Staphylococcus aureus strain V8 (protease V8) is a convenient method for the study of variants that involve large peptides such as alpha T-9 and alpha T-12b. We report here on Hb Valparaiso [alpha 88(F9)Ala-->Gly], a new neutral variant with a slight increase in oxygen affinity, that was identified by use of this strategy.

Female↗