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Biomedical subjects

D Bachir

Publications and source records attributed to D Bachir.

At least 19 recordsLinked to original sources
PubMed2006

The natural history of asymptomatic osteonecrosis of the femoral head in adults with sickle cell disease.

BACKGROUND: Osteonecrosis of the femoral head is a frequent complication in adult patients with sickle cell disease. However, little is known about the natural history of asymptomatic lesions. METHODS: One hundred and twenty-one patients (121 hips) with sickle cell disease and asymptomatic osteonecrosis of the femoral head that was contralateral to a hip with symptomatic osteonecrosis were identified with magnetic resonance imaging between 1985 and 1995. The lesions were graded with use of the Steinberg classification system. The patients were followed with annual plain radiographs. The mean duration of follow-up was fourteen years. RESULTS: At the time of the initial evaluation, fifty-six hips were classified as Steinberg stage 0, forty-two hips were classified as Steinberg stage I, and twenty-three hips were classified as Steinberg stage II. At the time of the most recent follow-up, pain had developed in 110 previously asymptomatic hips (91%) and collapse had occurred in ninety-three hips (77%). Symptoms always preceded collapse. Of the fifty-six hips that were classified as Steinberg stage 0 at the time of the initial evaluation, forty-seven (84%) had symptomatic osteonecrosis and thirty-four (61%) had collapse at the time of the most recent follow-up. Of the forty-two asymptomatic stage-I hips, forty (95%) became symptomatic within three years and thirty-six (86%) had collapse of the femoral head. Of the twenty-three asymptomatic stage-II hips, all became symptomatic within two years and all collapsed; the mean interval between the onset of pain and collapse was eleven months. At the time of the final follow-up, ninety-one hips (75%) had intractable pain and required surgery. CONCLUSIONS: Untreated asymptomatic osteonecrosis of the femoral head in patients with sickle cell disease has a high likelihood of progression to pain and collapse. Because of the high prevalence of complications after total hip arthroplasty in patients with this disease, consideration should be given to early surgical intervention with other procedures in an attempt to retard progression of the disease.

Adolescent↗
PubMed2005

[Acute splenic sequestration: a rare and severe complication of sickle cell anemia in adults. A case report].

INTRODUCTION: Acute splenic sequestration, a well-recognized complication of sickle cell syndromes, is characterized by a sudden decrease in haemoglobin concentration and marked painless splenomegaly. We report a case illustrating the outcome and the treatment options of this complication. CASE REPORT: A 45-year old homozygous woman developed acute splenic sequestration with severe anemia. Red blood cells transfusion led to transient improvement but a relapse-required splenectomy. Long-term outcome was favorable. CONCLUSION: Acute splenic sequestration is a severe complication mainly observed in children. Despite the severity of this complication, prompt diagnosis and appropriate therapy, and particularly red blood cells transfusions, led to a complete recovery. Splenectomy is required in the more severe form of the disease.

Acute Disease↗
PubMed2004

[Total hip arthroplasty for the treatment of septic hip arthritis in adults with sickle-cell disease].

PURPOSE OF THE STUDY: Septic hip arthritis is a recognized complication of sickle-cell disease. The incidence is difficult to assess but is significant since certain authors estimate that 11% of children with sickle-cell disease develop orthopedic complications. We report our experience with hip joint infection in adults with sickle-cell disease. MATERIAL AND METHODS: We diagnosed ten cases of hip joint infection in seven adults with sickle-cell disease. The characteristic feature of the septic arthritis was the development of a septic focus in a zone of osteonecrosis of the femoral head. Diagnosis was difficult due to the presence of prior hip disease and also the circumstances of development: other infectious foci, septicemia, distant osteomyelitis. The diagnosis was confirmed by joint puncture and isolation of the causal germ. Despite adapted antibiotics and immobilization with traction-suspension, hip joint destruction could not be prevented and all patients became bedridden. Surgery was therefore undertaken to remove the head and neck and institute local antibiotic treatment. A total hip prosthesis was implanted in all patients. RESULTS: At 2 to 12 years follow-up, all seven patients had nearly normal hip function (all 10 hips). Recurrent infection nevertheless developed in 2 hips, demonstrating the limitations of this technique.

Adult↗
PubMed2003

The natural history of symptomatic osteonecrosis in adults with sickle-cell disease.

BACKGROUND: Adult patients with sickle-cell disease are at risk for the development of osteonecrosis of the hip. However, there is little information in the literature about the rate of progression of osteonecrosis once symptoms begin. The purpose of this study was to evaluate the natural history of the symptomatic hip in adult patients with osteonecrosis and sickle-cell disease. METHODS: Ninety-two symptomatic hips in sixty-four consecutive adult patients with sickle-cell disease were initially evaluated between 1980 and 1987. Sixty symptomatic hips had radiographic evidence of osteonecrosis at the initial evaluation: forty-three were classified as stage II; two, as stage III; and fifteen, as stage IV, according to the system of Steinberg et al. The other thirty-two hips had lesions (stage I) that were evident only on magnetic resonance imaging. All patients were evaluated after a mean duration of follow-up of seventeen years. RESULTS: Of the seventy-five hips without collapse of the femoral head at the initial evaluation, sixty-five demonstrated collapse within five years after the diagnosis. The average time between the diagnosis and collapse was forty-two months for stage-I hips and thirty months for stage-II hips. At the most recent follow-up examination, ninety hips had had collapse of the femoral head and eighty-eight of the ninety-two hips had had surgery because of intractable pain. CONCLUSIONS: Symptomatic osteonecrosis of the hip in sickle-cell disease has a high likelihood of leading to femoral head collapse, necessitating surgical intervention. When osteonecrosis develops, the deterioration is rapid and, in most patients, operative intervention is necessary because of intractable pain. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Adolescent↗
PubMed2002

[Severe sickle cell anemia revealed in an adult by medullary necrosis].

INTRODUCTION: Drepanocytosis, even severe, may only be discovered in adults further to severe complications. OBSERVATION: A 44 year-old woman was hospitalised for a severe vaso-occlusive crisis, revealing a drepanocyte syndrome with heterozygote S-beta zero thalassemia. Evolution was marked by severe anaemia, the aregenerative nature of which, uncommon during vaso-occlusive crises and the absence of Parvovirus B19 infection, led to the diagnosis of medullar necrosis. Evolution was rapidly improved after transfusion of erythrocyte concentrations and symptomatic treatment of the pain. COMMENTS: Medullar necrosis is a rare entity with multiple causes. In severe drepanocyte syndromes it is concomitant to a severe vaso-occlusive syndrome, resulting from medullar ischemia due to specific microvascular damage.

Adult↗
PubMed2001

The nonexpression of CD36 on reticulocytes and mature red blood cells does not modify the clinical course of patients with sickle cell anemia.

It is thought that an increase in the adhesion of circulating reticulocytes to the vascular endothelium may initiate the vascular occlusion underlying the painful crises and organ failures typical of sickle cell disease (SCD). At least 2 receptors, usually present on reticulocytes, seem to be involved in this adhesion process: glycoprotein CD36 (glycoprotein IV) and integrin alpha(4)beta(1) (very late activation antigen--4). Recently, a high frequency of the platelet CD36--deficient phenotype was reported in black Africans. The frequency of this deficiency was similar in subjects with and without SCD. The role of CD36 in vaso-occlusion was then investigated by comparing the clinical course in 2 groups of black Africans homozygous for hemoglobin S, with and without CD36 deficiency, but similar in age, sex, geographical origin, number of alpha-globin genes, and beta-globin gene haplotype. Flow cytometry showed that CD36 was absent from the circulating red blood cells and reticulocytes of platelet CD36--deficient individuals but present on those from patients with normal platelet CD36 expression, and that alpha(4)beta(1) integrin levels were similar on the reticulocytes of the 2 groups. Neither clinical severity, as evaluated by the frequency and characteristics of vaso-occlusive events, nor biological data differed significantly in the 2 groups of patients. Finally, although CD36 has been suggested to play a critical role in the pathogenesis of vaso-occlusion, this study, despite including only a small number of patients, supports the idea that the modulation of expression of a single type of adhesion molecule is insufficient to counteract the pathological process leading to vaso-occlusion in SCD patients. (Blood. 2001;98:966-971)

Adolescent↗
PubMed2001

Endothelial dysfunction in patients with sickle cell disease is related to selective impairment of shear stress-mediated vasodilation.

Interactions between the endothelium and erythrocytes may contribute to the vascular complications of sickle cell disease (SCD). Endothelium-derived nitric oxide (NO) plays a major role in the regulation of vasomotor tone in response to wall shear stress (WSS) variations and pharmacologic stimuli. However, little is known about endothelial NO production in patients with steady-state SCD. We investigated endothelial NO production in response to flow or vasoactive agonists in 16 homozygous patients with steady-state SCD and 15 controls. Flow-mediated dilation (FMD), arterial diameter changes in response to 100% oxygen inhalation, blood viscosity, and calculated WSS were determined in all patients and controls. At baseline, WSS was higher in SCD patients than in controls, whereas arterial diameter was similar. In patients with SCD, FMD was impaired (1.73% +/- 0.44% vs 3.97% +/- 0.24% in the controls, P <.001) and vasoconstriction in response to 100% oxygen was abolished. Using venous occlusion plethysmography, forearm blood flow (FBF) was evaluated in response to acetylcholine, nitro-monomethyl-L-arginine (L-NMMA), and sodium nitroprusside (SNP) in subgroups of 9 controls and 7 patients with SCD. Acetylcholine induced a significantly greater FBF increase in the patients (9.7 +/- 2.9 mL/min/100 mL of forearm volume vs 2.5 +/- 1.5 mL/min/100 mL in the controls, P <.001), whereas responses to L-NMMA and SNP were similar. These results suggest that endothelial dysfunction may prevent the arterial diameter of patients with SCD from adapting to chronic or acute shear stress elevations. This may contribute to the pathophysiology of vaso-occlusive crisis in patients with SCD.

Acetylcholine↗
PubMed2001

[Sickle cell disease in adults: which emergency care by the internists?].

INTRODUCTION: Sickle cell disease is an inherited disease characterized by the presence of an abnormal haemoglobin. It is the most prevalent genetic disease at birth in the Ile-de-France area. Internists are involved in the management of acute complications, particularly acute vaso-occlusive crisis. CURRENT KNOWLEDGE AND KEY POINTS: Sickle cell disease can be complicated by acute vaso-occlusive crisis, chronic visceral involvement related to the ischaemic process, and infectious complications. In adults, acute vaso-occlusive crisis is the major clinical problem prompting admission to the hospital and the main cause of death. It mainly manifests by osteoarticular pain but other clinical complications can be observed such as acute chest syndrome, priapism, ischaemic or haemorrhagic stroke, abdominal pain and acute multivisceral failure. The treatment of acute vaso-occlusive crisis is symptomatic. Simple transfusion or partial exchange transfusion is required in the more severe form of vaso-occlusive crisis. FUTURE PROSPECTS AND PROJECTS: The management of adult patients with sickle cell disease must be based on a multidisciplinary approach. At the present time, more than 50% of patients survive beyond the fifth decade. This better and longer life in developed countries has resulted from basic investigations and symptomatic treatments.

Acute Disease↗
PubMed2001

Resveratrol, a natural dietary phytoalexin, possesses similar properties to hydroxyurea towards erythroid differentiation.

Resveratrol, a natural dietary polyphenol, has been postulated to be implicated in the cardioprotective effect of red wine and the low incidence of breast and prostate cancers among vegetarians and Orientals respectively. This compound inhibits ribonucleotide reductase as does hydroxyurea, the first therapeutic agent used in the treatment of sickle cell disease. Using the human erythroleukaemic K562 cell line as an in vitro model, we show here that 50 micromol/l of resveratrol induced a higher haemoglobin production (sevenfold) in K562 cells than 500 micromol/l of hydroxyurea (3.5-fold). This erythroid differentiation was linked to a dose- and time-dependent inhibition of cell proliferation associated with an equivalent increased expression of p21 mRNA, but with a higher increased level of p21 protein (sixfold) for cells treated with resveratrol than for those treated with hydroxyurea (1.5-fold). We also show that 50 micromol/l of resveratrol and 25 micromol/l of hydroxyurea induced variable but similar enhancements of fetal haemoglobin synthesis in cultured erythroid progenitors for the majority of the sickle cell patients studied. These inductions were linked to, but not correlated with, a variable decrease in erythroid burst-forming unit clone number. Taken together, these results show that resveratrol merits further investigations in sickle cell disease therapy.

Anemia, Sickle Cell↗
PubMed2000

Oral magnesium pidolate: effects of long-term administration in patients with sickle cell disease.

Prevention of erythrocyte dehydration by specific blockade of the transport pathways promoting loss of potassium (K) is a potential therapeutic strategy for sickle cell (SS) disease. Dietary magnesium (Mg) pidolate supplementation over a 4-week period has been shown to inhibit K-Cl co-transport and reduce dehydration. We report here the results in 17 of 20 patients with SS disease treated in an open-label unblinded study of the effects of long-term (6 months) oral Mg pidolate administration (540 mg Mg/d). A significant decrease (P < 0.0025) was observed with Mg therapy in the distribution widths for red cell mean cell haemoglobin concentration (MCHC) (haemoglobin distribution width; HDW), reticulocyte mean cell volume (red cell distribution width of reticulocytes; RDWr) and MCHC (reticulocyte HDW; HDWr), activity of red cell K-Cl co-transport, Na/Mg exchanger and Ca2+-activated (Gardos) K+ channel, whereas red cell K and Mg contents were significantly increased. Hb levels and absolute reticulocyte counts did not change with Mg therapy. Two patients did not complete the trial because of diarrhoea and one did not complete the trial for unrelated reasons. Although the median number of painful days in a 6-month period decreased from 15 (range 0-60) in the year before the trial to 1 (range 0-18; P < 0.0005) during the period of Mg therapy, no firm conclusion on therapeutic efficacy could be drawn from this unblinded open-label trial.

Administration, Oral↗
PubMed2000

Acute chest syndrome in adults with sickle cell disease.

STUDY OBJECTIVES: Acute chest syndrome (ACS) is a frequent and potentially severe pulmonary illness in sickle cell disease (SCD). The aim of the study was to report the clinical features and outcome of consecutive ACS episodes in adult patients in a French SCD center. All patients were treated according to an uniform therapeutic protocol applying transfusion only in the more severe clinical form of ACS. RESULTS: There were 107 consecutive episodes in 77 adult patients (mean age, 29 +/- 7 years; 78% hemoglobin [Hb] SS; 14% Hb SC; and 8% Hb Sbeta + thalassemia) over a 6-year period. Seventy-eight percent of our patients had an associated vaso-occlusive crisis that preceded the chest signs in half of the cases. Comparison between acute and baseline levels showed a statistically significant difference in Hb levels (drop of 1.6 to 2. 25 g/dL depending on Hb genotype), WBC count (increase of 9.2 +/- 8. 3 x 10(9)/L); platelet count (increase of 67 +/- 209 x 10(9)/L); and lactate dehydrogenase values (increase of 358 +/- 775 IU/L) in ACS patients. Hypercapnia was detected in 42% of patients without sign of narcotic abuse. We identified a high percentage of alveolar macrophages containing fat droplets in 31 of 43 (77%) patients who underwent BAL. Bacterial culture findings were almost always negative, but were performed after starting antibiotic therapy that was administered in 96 episodes. Transfusion was required in 50 of 107 ACS events (47%). Five patients died, and all were transfused. CONCLUSIONS: These results confirm that fat embolism is probably a frequent mechanism of ACS in adult patients. However, fat embolism was not associated with a more severe clinical course, suggesting that bronchoscopy and BAL have little impact on the management of these patients. Restricting transfusion to the most severe ACS cases does not seem to increase the mortality rate.

Acute Disease↗
PubMed1999

CD36 deficiency is frequent and can cause platelet immunization in Africans.

BACKGROUND: CD36 is expressed on several cell lineages. About 5 to 10 percent of Asians lack platelet membrane CD36 (pCD36), but the frequency of pCD36 deficiency in other ethnic groups is not known. Persons who are pCD36-negative are apparently healthy but can develop CD36 isoimmunization. STUDY DESIGN AND METHODS: The pCD36 phenotype was studied in 1885 subjects belonging either to a group of 1127 healthy French blood donors (almost all of whom were white Europeans) or to a group of 758 patients of known ethnic origin. RESULTS: No pCD36-negative persons were found among the blood donors. Only 1 of the 301 white European patients was pCD36-negative. In contrast, 16 of the 206 sub-Saharan Africans was pCD36-negative, a proportion higher than that among that black Caribbeans (1/148, p<0.01). The frequency of pCD36-negative patients was similar in blacks with and without sickle cell disease. Monocyte CD36 (mCD36) expression was studied in 15 of 22 pCD36-negative individuals: it was <10 percent in 7 subjects (type I deficiency) and between 12 and 100 percent in 8 others (type II deficiency). Thirteen pCD36-negative individuals had risk factors for immunization, and 4 had anti-CD36. Some had a history resembling posttransfusion purpura (n = 2), platelet transfusion refractoriness (n = 1), and recurrent miscarriage (n = 1). No correlation was found between immunization and the amount of mCD36. Anti-CD36 from an immunized type II-deficient woman reacted with monocytes from normal controls but not with monocytes from type I- or type II-deficient individuals, and thus it is postulated that mCD36 could be structurally different in normal and type II CD36-deficient individuals. CONCLUSION: CD36 deficiency is frequent in sub-Saharan Africans; development of anti-CD36 can lead to serious complications in multiply transfused patients, such as those with sicke cell disease.

Adult↗
PubMed1999

Preliminary report of a toxicity study of hydroxyurea in sickle cell disease. French Study Group on Sickle Cell Disease.

AIM: To evaluate the tolerance of hydroxyurea in children affected with sickle cell disease. DESIGN: Questionnaire study of French physicians likely to treat patients with sickle cell disease. Data were collected on 101 children with sickle cell disease, treated for a median of 22 months, 36 of whom were treated for more than three years. 13 children were younger than 5 years of age at inclusion. RESULTS: Hydroxyurea was stopped for medical reasons in 11 patients: 6 failures, 1 pregnancy, 1 cutaneous rash, 1 leg ulcer, 1 lupus. Acute lymphoblastic leukaemia occurred in a girl treated for 1.5 months with hydroxyurea, this short interval arguing against a causative association. One 17 year old boy had paraparesis after 8 years of treatment. CONCLUSIONS: No major short or medium term toxicity was related to hydroxyurea in this cohort of 101 children. However, the number of children treated for more than 3 years is too few to make firm conclusions on the long term tolerance of this drug.

Adolescent↗
PubMed1999

[Management of adults with sickle cell anemia].

The management of adults with sickle cell disease should be geared to the profile of the disease in adulthood. The chronic hemolytic anemia impacts everyday activities. Paroxysmal complications include painful vasoocclusive crises, acute chest syndrome, priapism, and infections. Potentially life-threatening chronic complications should be detected and treated early; they include cardiopulmonary, renal, and hepatic involvement. Osteonecrosis of the hip can result in functional impairment. Pregnancy and anesthesia require special precautions. A multifaceted personalized management program, if possible at a sickle cell disease center working closely with other health care providers and social workers, offers the best hope for providing ever-increasing gains in quality of life for sickle cell disease patients.

Adult↗
PubMed1998

Genetic and hematological studies in a group of 114 adult patients with SC sickle cell disease.

The clinical and biological heterogeneity of sickle cell hemoglobin (Hb) C disease (SC disease) is similar to sickle cell anemia, but has a much milder course. The effect of genetic factors such as alpha thalassemia or beta-globin gene haplotype has been analyzed in a limited number of cases. In this work, we report about 114 adult SC patients, aged 15 to 65 years (M/F = 0.93). The frequency of deletional alpha thalassemia (alpha(-3.7)) was found to be about 35%. The coinheritance of an alpha-thalassemia trait with SC disease had no effect on the hemoglobin level but hemolysis was significantly reduced. In these patients, as described for homozygous Hb S individuals, the Hb F level was higher in females than in males and in individuals carrying the beta(s)-Senegal haplotype. This haplotype involves the presence of an Xmnl site 5' to Ggamma, which is considered responsible for an increased Ggamma/Agamma ratio. Our survey showed that some genetic factors may modulate hematological parameters in SC disease.

Adolescent↗
PubMed1998

A new sickle cell disease phenotype associating Hb S trait, severe pyruvate kinase deficiency (PK Conakry), and an alpha2 globin gene variant (Hb Conakry).

A Guinean woman, heterozygous for haemoglobin (Hb) S, was studied because of episodes of marked anaemia, repeated typical metaphyseal painful crises and haemosiderosis. Her sickling syndrome resulted from the association of Hb S trait with a severe pyruvate kinase deficiency leading to a 2,3-DPG concentration of twice normal levels. Sequence of the PK-R gene revealed an undescribed mutation in the homozygous or hemizygous state within exon 5 (nucleotide 2670 C-->A), leading to the interchange of Ser 130 into Tyr (PK Conakry). In addition, the patient carried a new haemoglobin variant, Hb Conakry [alpha80(F1) Leu-->Val], which seemed to have a mild effect. The high intraerythrocytic 2,3-DPG concentration induced by the PK deficiency resulted in a decreased oxygen affinity which favoured sickling to a level almost similar to that of Hb S/C compound heterozygous patients. This was confirmed by oxygen binding measurements of Hb A/Hb S erythrocytes in which 2,3-DPG content was modified in vitro. Hysteresis between deoxy- and reoxygenation curves, as well as increase in the n(max) value, demonstrated that the extent of HbS polymerization in the propositus was almost the same as that of RBCs from a homozygous sickle cell patient or those of an A/S heterozygous patient with an artificial in vitro increase of 2,3-DPG concentration.

Adult↗