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Biomedical subjects

F Galacteros

Publications and source records attributed to F Galacteros.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Natural history of hip necrosis in sickle cell disease. Apropos of 104 necroses].

The authors have followed 140 patients with sickle cell disease anemia (101 cases) or related hemoglobinopathies (39 cases). Among them hip involvement was noted in 55 (104 hips). Forty three times the hip involvement occurred in childhood and twelve times in adult life. When the necrosis appeared in childhood (84 hips) the average age was twelve. The deformity involved the femoral head (coxa plana, coxa magna) as well as the neck (short neck, coxa vara). After an average follow-up of nineteen years, clinical and radiological examinations evidenced 64 functional impairments and 25 arthrosis, 10 of which have already been operated on. The necrosis appearing during adult life (20 hips) had the same outcome as idiopathic necroses, leading rapidly to arthrosis after collapse of the sequestrum. It seems that the etiology of the necroses is linked to rheologic disorders, the deformity of the red cells causing arteriolar thromboses. In this series the hip disease was correlated with sickle cell retinopathy as defined after angiography. On the contrary there was no correlation with the severity of anemia, its treatment, the ethnical origin of the patient.

Adolescent↗
PubMed1989

Centrifugal pump or pneumatic ventricle for short-term mechanical circulatory support?

Two comparable groups of four Holstein calves were implanted with different left ventricle assist devices: the Centrimed centrifugal pump (CP) (Sarns Inc.) or the UTAH 85 VAD pneumatic ventricle (University of Utah). Operative procedure, inflow and outflow cannulae, monitoring, heparinization, were identical in both groups. No transfusion was ever required. The study was terminated after three days and autopsy was performed on the calves. Left ventricular unloading provided by both devices was complete (LVEDP less than 1 mmHg) and identical. LV bypassed flow rate was higher in CP (0.045 L/min/kg) than in UTAH 85 VAD (0.035 L/min/kg) but with no statistical difference. Blood trauma was comparable in the two groups. Daily blood samples did not show any significant changes from baseline values in creatinine, hematocrit, fibrinogen. Platelet loss from initial level was 30%; serum lactate dehydrogenase rose 150% with no significant difference in the two groups; plasma free hemoglobin never reached significant values. At autopsy, thrombotic deposits on cannuale and renal infarction rate were similar. CP housing had to be changed every day, whereas no technical failure was ever observed with the UTAH 85 VAD. Clinical response and blood damage of the two pumps used as LVAD were the same. Considering the CP has to be replaced every 24 h, the cost of three CP's would be comparable to one Utah UVAD-85 if polyurethane tricusp semi-lunar valves are used in the latter. Until the UTAH-85 VAD becomes commercially available, simple valveless low-cost CP are very attractive for short-term mechanical support.

Animals↗
PubMed1989

Hemoglobin Köln occurring in association with a beta zero thalassemia: hematologic and functional consequences.

Hemoglobin (Hb) Köln-beta zero thalassemia compound heterozygosity was discovered in a young Greek patient. This gave us the unique opportunity for studying the functional properties of this unstable high-oxygen affinity hemoglobin variant in red cells containing almost pure Hb Köln. The red cells of the proposita exhibit morphological alterations and hematologic indices corresponding to the presence of an unstable Hb and beta thalassemia. Globin chain synthesis confirmed the association with a beta zero thalassemia gene. Oxygen-binding curves for these cells were biphasic, indicating the presence of both heme-saturated and of approximately 20% of non-cooperative Hb Köln. The major component exhibits an increased oxygen affinity, reduced cooperativeness, and normal alkaline Bohr effect. The 35-year-old proposita is active, has not been splenectomized, and has not been transfused in several years.

Adult↗
PubMed1988

Endogenous calcium in sickle cells does not activate polyphosphoinositide phospholipase C.

Sickle-cell-anaemia erythrocytes (SS cells) are known to have a high Ca2+ content (particularly the dense cell fraction) and to take up Ca2+ on deoxygenation. It has been reported that this high Ca2+ was responsible for the activation of the Ca2+-dependent K+ loss, and of the Ca2+-sensitive polyphosphoinositide phospholipase C (PIC) in dense SS cells. We found that, either in the total population of SS cells or in the light or dense fractions, the content of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] was not changed, whereas that of phosphatidylinositol 4-phosphate was increased and that of phosphatidic acid (PtdOH) was decreased compared with normal (AA) erythrocytes. Deoxygenation-induced Ca2+ entry into SS cells did not change the concentration or, in 32P-prelabelled cells, the radioactivity of polyphosphoinositides and PtdOH. It also failed to induce the formation of inositol 1,4,5-trisphosphate, the product of PtdIns(4,5)P2 hydrolysis by PIC, which was measured by an original method using ion-pair reverse-phase h.p.l.c. Thus there was no evidence of an endogenous Ca2+ effect on the PIC activity in SS cells, in agreement with the demonstration that the excess Ca2+ in SS cells is compartmentalized into internal vesicles and unavailable as free Ca2+. The 32P incorporation in polyphosphoinositides and PtdOH was markedly higher in SS than in AA cells, but this increase was the same in both dense and light SS cells. The increase in the turnover of these phospholipids in SS cells is consistent either with an activation of the lipid kinases and phosphatases or with perturbation in the metabolic compartmentation of these lipids.

Adenosine Triphosphate↗
PubMed1988

Identification of some abnormal haemoglobins by fast atom bombardment mass spectrometry and fast atom bombardment tandem mass spectrometry.

The characterization of two abnormal human haemoglobins by fast atom bombardment (FAB) mapping is presented. The first variant, called 'R', exhibits a tryptic FAB map identical to that of normal haemoglobin. However, using Staphylococcus protease V8, a peptide containing the carboxyl end of the beta-chain exhibits a mass shift down to 300 mass units. This clearly indicates the deletion of the two last amino acids of the beta-chain. The second variant, called 'Grenoble', is due to two different modifications of the beta-chain. The location of the Pro----Ser exchange on peptide T5 is achieved by the collisionally activated dissociation mass analyzed ion kinetic energy spectra of the corresponding [MH]+ ion. The m/z value of that peptide indicated a supplementary acid----amide modification, which was located by amino acid sequencing using chemical methods. This work concludes with the necessity of using complementary methods for achieving rapid determinations of abnormal proteins with minute amounts.

Amino Acid Sequence↗
PubMed1988

Hb Tunis [alpha 2 beta 2 124 (H2)Pro----Ser], a new beta chain variant identified by HPLC.

During a routine hematological investigation of a child from Tunis, a silent hemoglobin variant was discovered by isoelectric-focusing. This variant was not detectable by conventional electrophoretic methods, had normal stability, expression, and oxygen affinity, and did not produce any clinical symptoms. This new variant beta 124(H2)Pro----Ser was named Hb Tunis.

Amino Acids↗
PubMed1988

Hemoglobin Brest [beta 127 (H5)Gln----Lys] a new unstable human hemoglobin variant located at the alpha 1 beta 1 interface with specific electrophoretic behavior.

Hb Brest [beta 127 (H5)Gln----Lys] is a new unstable variant located at the alpha 1 beta 1 interface at the same position as Hb Complutense [beta 127(H5)Gln----Glu]. In each of these, the substitution produces a distinct alteration in charge, yet both variants move with Hb A in conventional electrophoresis. This peculiar electrophoretical behavior may be due to the molecular position of the modified residue, which is deeply buried inside the tetramer.

Amino Acid Sequence↗
PubMed1988

Hemoglobin Saverne: a new variant with elongated beta chains: structural and functional properties.

A 26-year-old French woman born in Saverne (France) was found to have Heinz body hemolytic anemia. Isoelectrofocusing showed the presence of an abnormal band amounting to 35% of the total hemoglobin concentration, suggesting a beta variant. Structural analysis of the abnormal beta chain showed an elongated C-terminal segment. Histidine 143 is replaced by a proline and the C-terminal sequence is identical to the corresponding segment of Hb Cranston. This new variant, named Hb Saverne, has beta chains composed of 156 amino acid residues. Studies of its functional properties showed that Hb Saverne is an unstable, high affinity variant with low cooperativity.

Adult↗
PubMed1987

The calmodulin-stimulated (Ca2+ + Mg2+)-ATPase in hemoglobin S erythrocyte membranes: effects of sickling and oxidative agents.

A decrease in the reactivity of erythrocyte membrane (Ca2+ + Mg2+)-ATPase to calmodulin stimulation has been observed in aging red cells and in various types of hemolytic anemias, particularly in sickle red cell membranes. Unlike the aging process, the defect in the (Ca2+ + Mg2+)-ATPase from SS red blood cells is not secondary to a decrease in calmodulin activity and is already present in the least dense SS red blood cells separated on a discontinuous density gradient. Deoxygenated AS red cells were forced to sickle by lowering the pH, raising the osmolarity of the buffer (sickling pulse). Under these conditions an inhibition of the calmodulin-stimulated enzyme was observed only if several cycles of oxygenation/deoxygenation were applied. No alteration of the enzyme could be detected after submitting AS red blood cells to other conditions or in AA red blood cells submitted to the same treatments. This suggests that oxidative processes are involved in the alterations of the (Ca2+ + Mg2+)-ATPase activity. Treatment of membranes from AA erythrocytes by thiol group reagents and malondialdehyde, a by-product of auto-oxidation of membrane unsaturated lipids and a cross-linking agent of cytoskeletal proteins, led to a partial inhibition of the calmodulin-stimulated (Ca2+ + Mg2+)-ATPase. We postulate that the hyperproduction of free radicals described in the SS red blood cells and involved in the destabilization of the membrane may be also responsible for the (Ca2+ + Mg2+)-ATPase failure.

Anemia, Sickle Cell↗
PubMed1987

A new case of Hb Little Rock [beta 143(H21)His----Gln], a high affinity variant. Study during pregnancy.

A new case of Hb Little Rock [beta 143(H21)His----Gln] is described. This high affinity variant (P50 = 15 mm Hg in whole cells) has a nearly normal cooperativity. The abnormal beta chain is readily detectable using urea-Triton X-100 electrophoresis. The altered beta T-14 peptide was separated by high performance liquid chromatography. The proposita was followed during a pregnancy. Oxygen unloading was reduced, but normal oxygen loading was maintained in the fetus. There were neither placental abnormalities, nor intrauterine growth retardation.

Adult↗
PubMed1987

Further characterization of Hb Henri Mondor or alpha 2 beta 2(26)(B8)Glu----Val.

A second case of Hb Henri Mondor is reported. The subject, homozygous for Hb Henri Mondor, is of Algerian origin. The electrophoretical behavior and structural characterization are given and discussed. Hb Henri Mondor, which is characterized by the replacement of the lysine residue in position beta 26, as is the case for Hb E, has normal functional properties and is normally expressed.

Amino Acids↗
PubMed1987

[Major beta-thalassemia and bone marrow allograft. Two cases and a study of the literature].

A 5 year 9 month-old boy has received a bone marrow allograft for beta-thalassaemia major. Conditioning included busulfan: 16 mg/kg, cyclophosphamide 200 mg/kg and a (6 Gy) thoracoabdominal irradiation. After a 16 months follow-up, the child is currently in complete remission without treatment with all the markers of his donor. His 9 year-old sister has been allografted for beta-thalassaemia major, with the same conditioning regimen. After engraftment, rejection occurred at day 85 with severe aplastic anaemia. A second graft was performed with the same donor without engraftment and the patient died at day 18 of pneumonitis. A review of the literature is proposed and the ethical choices are discussed.

Bone Marrow Transplantation↗