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Biomedical subjects

D Bonnet

Publications and source records attributed to D Bonnet.

At least 145 records · Page 8Linked to original sources
PubMed1999

[Treatment of obstruction of prosthetic conduct by percutaneous implantation of stents].

Prosthetic conduits, with or without biological valves, are often inserted in surgical procedures to correct or palliate cardiac malformations. The principal problem is degeneration which causes variable degrees of obstruction requiring reoperation for their replacement. The aims of this study were to assess the feasibility, safety and efficacy of a non-surgical method of treating these obstructive prostheses by dilatation-implantation of a metallic vascular endoprosthesis (stenting). Thirteen patients were treated (age range 7.7 to 36 years; mean: 15 years). Eight had pulmonary atresia with a ventricular septal defect corrected by a valved conduit from the right ventricle to the pulmonary artery which became obstructive nearly 10 years later: the implantation of the stent reduced the transconduit pressure gradient in all cases except one who had not undergone closure of the septal defect in which the cyanosis was improved. There are two cases of obstruction of a modified Blalock anastomosis in which the stent revascularised the shunt with improvement in cyanosis. In the final 3 cases, the whole Fontan procedure was compromised by obstruction of a conduit incorporated in the system, and which dilatation with stenting considerably improved. The efficacy of the procedure was constant with no complications other than rupture of the balloon in 3 cases. The good results were maintained for an average of 7.3 months (range 1 to 25 months), but it was necessary to redilate one restenosed stent after 8 months. Dilatation followed by stenting in obstructive cardiovascular prostheses is a simple, safe and effective alternative to surgical reoperation.

Adolescent↗
PubMed1999

[Prenatal diagnosis of transposition of great vessels reduces neonatal morbidity and mortality].

Transposition of the great arteries (TGA) is a common malformation which sometimes has a dramatic presentation at birth but which is completely curable with early and appropriate initial management. Antenatal diagnosis of this condition may change the neonatal prognosis. The authors compared morbidity and mortality in the pre- and postoperative periods of 68 neonates with an antenatal diagnosis of TGA (foetal diagnosis) with that of 250 neonates in whom the diagnosis was made after birth (neonatal diagnosis). The delay before admission to the department was 2 +/- 2.8 hours in the foetal group and 73 +/- 210 hours in the neonatal group (p < 0.01). Severe haemodynamic distress (metabolic acidosis, multi-organ failure) were more common in the neonatal group (p < 0.01). Management on admission was identical in the two groups (p > 0.05). The preoperative mortality was 15/250 in the neonatal group (6%, 95% CI = 3-9%) compared with 0/68 in the foetal group (p < 0.05). The postoperative morbidity was comparable in the two groups (25/235 and 6/68) but the hospital stay was longer in the neonatal group (30 +/- 17 versus 24 +/- 11 days, p < 0.01). Finally, postoperative mortality was significantly higher in the neonatal group (20/235 compared with 0/68, p < 0.01) although the risk factors of death at arterial switch surgery were identical in the two groups. Therefore, antenatal diagnosis of TGA reduces neonatal morbidity and mortality in this condition. Antenatal diagnosis must be developed by the education of obstetricians. The transfer of mothers with a foetus affected by TGA to centres capable of assuming the initial management, sometimes during labour, is essential.

Female↗
PubMed1999

[An anterior mediastinal mass].

A 50-year-old man developed a bronchogenic cyst complicated by hemorrhage. A complete radiographic chest work-up provided a reliable diagnostic approach. Bronchogenic cysts are usually asymptomatic incidental discoveries. Chest ultrasonography confirms the cystic nature of the mediastinal mass. Computed tomography scan and especially magnetic resonance imaging further support the diagnosis and are helpful for guiding surgery. Surgery is required because of the unpredictable risk of hemorrhage, infection or enlargement.

Biopsy↗
PubMed1999

[Cyclophosphamide-induced interstitial pneumopathy. Course data of bronchoalveolar lavage apropos of a case and review of the literature].

A patient treated with cyclophosphamide for breast cancer developed functional and clinicoradiological signs of sub-acute diffuse interstitial pneumopathy. Bronchoalveolar lavage revealed lymphocyte alveolitis. Differential diagnoses were excluded and the course was favorable after cyclophosphamide withdrawal. The bronchoalveolar lavage results obtained initially and at follow-up and two previous lavages reported in the literature demonstrate the importance of this examination in the diagnosis of drug-induced pneumopathy.

Adult↗
PubMed1999

[Metabolic and genetic investigations in childhood cardiomyopathies].

Metabolic cardiomyopathy of babies and children accounts for approximately 15% of all cardiomyopathies presenting at these ages. The confirmation of the aetiology is essential for treatment, which is rarely curative. For establishing a prognosis which is often poor, and, above all, for family counselling in cases of mendelian transmission or mitochondrial disease. Cardiomyopathy due to glycogen (Pompe's disease) or mucopolysaccharide (Hurler's disease) disorders are easy to diagnose because of obvious extracardiac manifestations. The diagnosis of the enzyme deficiency only requires a blood and/or urine test. Cardiomyopathies due to a deficit of oxidative metabolism are usually associated with multi-system abnormalities but may be isolated or the presenting sign of the deficit. The diagnosis should be suspected in cases of a positive family history of cardiomyopathy or sudden death, of co-sanguinity, of unusual or unexplained extracardiac disease, of atypical ECG changes or of hypoglycaemia. Chromatography of organic acids, analysis of acylcarnitines and -oxidation of the fatty acid oxidation. Of these conditions, only primary carnitine deficits are curable. The diagnosis of mitochondrial cardiomyopathy is based on the ratios of oxidoreduction and, above all, on spectrophotometric analysis of the respiratory chain complexes in skeletal or cardiac muscle (when the heart is the only organ involved). Genetic counselling is difficult and punctual mutations or deletions of mitochondrial DNA are rarely observed, and also few nuclear genes coding for the proteins of the respiratory chain have been identified to this day.

Cardiomyopathies↗
PubMed1998

Ebstein anomaly associated with rearrangements of chromosomal region 11q.

Ebstein anomaly (EA) is a relatively uncommon congenital heart defect and it is very rarely associated with a chromosomal anomaly. We report two distinct rearrangements of the chromosomal region 11q arm in two unrelated patients with Ebstein anomaly, renal malformation, minor anomalies, and the Pierre Robin sequence. The first patient had an interstitial deletion of chromosome 11 [46,XY,del(11)(11q21q23), and the other had a tertiary trisomy of chromosome 11qter (47,XX,+der(22)t(11;22)(q23;q11.2) Its association with either a chromosome 11q deletion or a duplication in some individuals suggests that a rearrangement of the 11q region is likely to cause a shift of the individuals' underlying liability to develop EA above a certain threshold.

Chromosome Aberrations↗
PubMed1998

Treatment of non-obese diabetic (NOD)/Severe-combined immunodeficient mice (SCID) with flt3 ligand and interleukin-7 impairs the B-lineage commitment of repopulating cells after transplantation of human hematopoietic cells.

Until recently, the identification of cellular factors that govern the developmental program of human stem cells has been difficult due to the absence of repopulation assays that detect human stem cells. The transplantation of human bone marrow (BM) or cord blood (CB) into non-obese diabetic (NOD)/severe-combined immunodeficient (SCID) mice has enabled identification of primitive human cells capable of multilineage repopulation of NOD/SCID mice (termed the SCID-repopulating cell [SRC]). Here, we examined the effect of long-term in vivo treatment with various combinations of human cytokines on the developmental program of SRC. Detailed flow cytometric analysis of engrafted mice indicated that the vast majority of the human graft of untreated mice was comprised of B lymphocytes at various stages of development as well as myeloid and primitive cells; T cells were not reproducibly detected. Many studies, including murine in vitro and in vivo data and human in vitro experiments, have suggested that flt3 ligand (FL) and/or Interleukin-7 (IL-7) promotes T- and B-cell development. Unexpectedly, we found that treatment of engrafted mice with the FL/IL-7 combination did not induce human T- or B-cell development, but instead markedly reduced B-cell development with a concomitant shift in the lineage distribution towards the myeloid lineage. Effects on lineage distribution were similar in engrafted mice transplanted with highly purified cells indicating that the action of the cytokines was not via cotransplanted mature cells from CB or BM cells. These data show that the lineage development of the human graft in NOD/SCID mice can be modulated by administration of human cytokines providing a valuable tool to evaluate the in vivo action of human cytokines on human repopulating cells.

Animals↗
PubMed1998

CHARGE syndrome: report of 47 cases and review.

The acronym CHARGE refers to a syndrome of unknown cause. Here we report on 47 CHARGE patients evaluated for the frequency of major anomalies, namely coloboma (79%), heart malformation (85%), choanal atresia (57%), growth and/or mental retardation (100%), genital anomalies (34%), ear anomalies (91%), and/or deafness (62%). In addition, we comment on anomalies observed very frequently in neonates and infants with the CHARGE syndrome, including, minor facial anomalies, neonatal brain stem dysfunction with cranial nerve palsy, and, mostly, internal ear anomalies such as semicircular canal hypoplasia that were found in each patient that could be tested. We propose several criteria for poor survival including male gender, central nervous system and/or oesophageal malformations, and bilateral choanal atresia. No predictive factor regarding developmental prognosis could be identified in our series. A significantly higher mean paternal age at conception together with concordance in monozygotic twins and the existence of rare familial cases support the role of genetic factors such as de novo mutation of a dominant gene or subtle sub-microscopic chromosome rearrangement. Finally, the combination of malformations in CHARGE syndrome strongly supports the view that this multiple congenital anomalies/mental retardation syndrome is a polytopic developmental field defect involving the neural tube and the neural crests cells.

Abnormalities, Multiple↗
PubMed1998

Prevalence of the microdeletion 22q11 in newborn infants with congenital conotruncal cardiac anomalies.

UNLABELLED: Conotruncal malformations account for about 50% of congenital heart defects diagnosed in newborns. We studied prospectively 104 patients admitted in our neonatal intensive care unit for conotruncal defects by fluorescence in situ hybridization to estimate the prevalence of the interstitial deletion in this category of congenital heart disease. Cardiac phenotypes were: truncus arteriosus (17), interrupted aortic arch (18), tetralogy of Fallot with or without pulmonary valve atresia (55), tetralogy of Fallot with absent pulmonary valves (5), ventricular septal defect with malalignment of the conal septum (9). We discovered a microdeletion 22q11 at loci D22S39 or D22S398 in 50 newborns (48%). The prevalence of this microdeletion in different groups of conotruncal defects was: truncus arteriosus 7/17, interrupted aortic arch 16/18, tetralogy of Fallot 19/55, absent pulmonary valves 2/5, and ventricular septal defect 6/9 respectively. Only two patients without any clinical or biological feature of the so called CATCH22 syndrome exhibited the deletion. Parental studies confirmed that the deletion occurred de novo in 47/50 cases (three parental microdeletions). On the other hand, recurrence of conotruncal heart defects in families of "undeleted probands" was higher than expected (13%). CONCLUSION: In 50/104 newborns with conotruncal defects, an interstitial deletion 22q11 was found. Fluorescence in Situ Hybridization should be performed in newborn infants with conotruncal defect and at least one additional manifestation of the CATCH22 phenotype.

Chromosome Deletion↗
PubMed1998

Fatty acid beta-oxidation deficiency masquerading as fulminant myocarditis.

We present a 9-month-old child presenting with acute cardiomyopathy and fever following a viral illness. He was diagnosed to have acute myocarditis, was proposed for an external hemodynamic assistance but died of ventricular tachycardia. Post-mortem data revealed a very-long-chain acylcoenzyme A dehydrogenase deficiency. Our report raises awareness on the interest for preserving tissue samples and for performing a metabolic screening in acute childhood cardiomyopathy.

Acyl-CoA Dehydrogenase↗
PubMed1998

[Recommendations for the treatment of recurrent supraventricular tachycardia in infants].

AIM: The effectiveness and safety of antiarrhythmic agents, mostly digoxin and amiodarone given to prevent recurrences, were compared in 141 infants of less than 1 year (77% < 1 month) with re-entrant supraventricular tachycardia. RESULTS: Digoxin was the drug of first choice in 114 patients at a dose of 10-20 micrograms/kg/d and was effective in 74 cases (65%). Amiodarone was used as first line therapy or after failure of digoxin. It was given at a maintenance dose of 250 mg/m2/d, alone in 22 infants and together with digoxin in another 36; it was effective in 56 cases (96.5%). Early adverse events occurred in six patients receiving digoxin: ventricular fibrillation requiring cardioversion in three, two of whom had Wolff-Parkinson-White syndrome, significant sinus bradycardia in two, accidental overload in one. At further follow-up, one child treated with digoxin but having also gastroesophageal reflux, died suddenly at 3 months of age; autopsy was normal and the digoxin blood level was 3 ng/mL. Among the 58 infants who received amiodarone, there were no proarrhythmia, a slight and transient increase in TSH in six infants and only one required a short-term treatment for hypothyroidism. Prophylactic therapy was maintained for 6 to 12 months and only ten patients had recurrences in the year following withdrawal. CONCLUSION: Amiodarone was found to be safer and more effective than digoxin. No significant side-effect was demonstrated in infants receiving a short-term treatment. Amiodarone may be proposed as first line therapy for prophylaxis of re-entrant supraventricular tachycardia in infancy, especially for those patients with reentry and Wolff-Parkinson-White syndrome.

Amiodarone↗
PubMed1998

A newly discovered class of human hematopoietic cells with SCID-repopulating activity.

The detection of primitive hematopoietic cells based on repopulation of immune-deficient mice is a powerful tool to characterize the human stem-cell compartment. Here, we identify a newly discovered human repopulating cell, distinct from previously identified repopulating cells, that initiates multilineage hematopoiesis in NOD/SCID mice. We call such cells CD34neg-SCID repopulating cells, or CD34neg-SRC. CD34neg-SRC are restricted to a Lin-CD34-CD38- population without detectable surface markers for multiple lineages and CD38 or those previously associated with stem cells (HLA-DR, Thy-1 and CD34). In contrast to CD34+ subfractions, Lin-CD34-CD38- cells have low clonogenicity in short-and long-term in vitro assays. The number of CD34neg-SRC increased in short-term suspension cultures in conditions that did not maintain SRC derived from CD34+ populations, providing independent biological evidence of their distinctiveness. The identification of this newly discovered cell demonstrates complexity of the organization of the human stem-cell compartment and has important implications for clinical applications involving stem-cell transplantation.

Animals↗
PubMed1998

Efficiency of metabolic screening in childhood cardiomyopathies.

AIM: To estimate the efficiency of metabolic screening in children's cardiomyopathy. METHODS AND RESULTS: Blood glucose, lactate, pyruvate and ketone body, and carnitine levels were measured in 58 children referred with a cardiomyopathy of unknown origin. Organic acids, amino acids, oxidation of [1-14C] fatty acids to CO2 and dehydrogenation of [9,10(-3)H] fatty acids by lymphocytes were measured. Mitochondrial respiratory chain complex activity was measured in skeletal muscle and in endomyocardial biopsies. Acid a-glucosidase activity was measured in infants with hypertrophic cardio-myopathy. The prevalence of metabolic disorders was 22.4% (13/58-CL95%; 11.4-33.3%): four infants had a storage disease (Pompe's disease (3), Hurler's disease (1); two patients had a fatty acid beta-oxidation defect (systemic carnitine deficiency (1) and very-long chain acyl-CoA dehydrogenase deficiency (1)); respiratory enzyme deficiency was diagnosed in seven patients. This defect was confined to the myocardium in six. In the remaining 45 patients, metabolic screening was unrevealing. CONCLUSION: Metabolic screening should be performed in all children with cardiomyopathy as the prevalence of metabolic disorders is high in this population. This may help to define therapeutic strategy and to improve genetic counselling.

Adolescent↗
PubMed1998

Left ventricular ejection fraction in children measured by three-dimensional echocardiography using a new transthoracic integrated 3D-probe. A comparison with equilibrium radionuclide angiography.

BACKGROUND: Three-dimensional echocardiography allows calculation of left ventricular ejection fraction without geometric assumption on the ventricular shape. Our aim was to validate this technique in a paediatric population with distorted ventricles. METHODS: Twenty-one patients aged 6 months to 17 years underwent equilibrium radionuclide angiography and three-dimensional echocardiography. Fourteen patients had dilated cardiomyopathy and seven had univentricular hearts. A new, easy to handle, transthoracic rotational probe was used and motion artefacts were limited during the rotation (3 degrees intervals with ECG and respiratory gating). Left ventricular volumes and ejection fraction were calculated using the Simpson's rule with 12 slices. RESULTS: Three-dimensional echocardiography correlated well with equilibrium radionuclide angiography for ejection fraction measurement (r = 0.90; the mean difference between the two methods being 3.8 +/- 6%). Intra-observer and inter-observer variabilities for 3D echocardiography were 2.4% and 4.5%. CONCLUSIONS: Three-dimensional echocardiography is an accurate, non-invasive, and reproducible methods to measure left ventricular ejection fraction in children.

Adolescent↗
PubMed1998

Relation of genotype 22q11 deletion to phenotype of pulmonary vessels in tetralogy of Fallot and pulmonary atresia-ventricular septal defect.

OBJECTIVE: To compare the morphology of the pulmonary vessels in tetralogy of Fallot or pulmonary atresia-ventricular septal defect (PA-VSD) with (del22q) and without 22Q11 deletion (non-del22q). PATIENTS: 94 consecutive infants (54 with tetralogy of Fallot, 40 with PA-VSD) were studied using ultrasound and catheterisation. MOLECULAR INVESTIGATIONS: Identification of the 22q deletion was performed either by fluorescent in situ hybridisation or polymerisation chain reaction genotyping. RESULTS: 25 patients were del22q (16/40 (40%) PA-VSD v 9/54 (17%) tetralogy of Fallot; p < 0.02). Major aortopulmonary collateral arteries was more common in patients with PA-VSD-del22q (p < 0.03). Such collaterals were identified in 13 patients: 10 del22q and three non-del22q (p < 0.001). The size of the right and left pulmonary arteries expressed as a standard deviation (SD) difference of the normal range was -4.2 (quartiles -5.3 and -2.9) for PA-VSD del22q, and -2.6 (-3.1 and -1.8) for PA-VSD non-del22q (p = 0.02). The mean (SD) difference between the measured and theoretical Nakata index was -373 (94) for PA-VSD del22q v -245 (93) in PA-VSD non-del22q (p = 0.0002). In tetralogy of Fallot patients with and without del22q, the size of the pulmonary arteries was similar (p = 0.6). CONCLUSIONS: A "specific" phenotype could be defined in patients with deletion: PA-VSD, major aortopulmonary collateral arteries with complex loop morphology, and small central pulmonary arteries. Differences in the morphology of the pulmonary vessels may indicate a different timing of the faulty developmental pathway in patients with and without 22q11 deletion.

Aorta↗