Search PubMed⌕ Search

Biomedical subjects

D Bonnet

Publications and source records attributed to D Bonnet.

At least 199 records · Page 11Linked to original sources
PubMed1997

[Travel and patients with allergies].

By changing their surroundings and lifestyle, travelers with allergic conditions exposed themselves to new risks. The main perennial allergens are house dust mites which thrive in tropical areas and can be especially sensitizing. The risk of seasonal reactions to grass-pollens varies from region to region. Reactions to some highly sensitizing respiratory allergens can occur in travelers who return to regions where they were previously exposed. Subjects with food allergies should beware of possible reactions to ingredients in exotic dishes. The bites of several insects can cause anaphylactic reactions. Some medications required for tropical travel (e.g. antimalarial drugs) can trigger severe hypersensitivity reactions. Avoidance of allergens is more difficult during travel. Travelers with allergic conditions should carry alert identification cards and medications for routine as well as emergency treatment including self-injectable adrenaline.

Humans↗
PubMed1997

[A tropical pulmonary nodule].

The authors report a case of american pulmonary histoplasmosis discovered by chance on a chest radiograph in a non immunocompromised patient, back from a stay in French Guyana. Confronted with the negativity of usual mycotic research, diagnosis has been made thanks to wedge excision by video-assisted thoracic surgery. The authors briefly sum up the recent facts regarding this imported infection, stressing the interest of a direct approach by surgical practices not very invasive that allow to eliminate with certainty neoplasm or tuberculosis.

Adult↗
PubMed1996

Key role of alkanoic acids on the spectral properties, activity, and active-site stability of iron-containing nitrile hydratase from Brevibacterium R312.

Interaction of n-butyric acid with dialyzed nitrile hydratase from Brevibacterium R312, which is characterized by a charge-transfer band at 680 nm and EPR signals typical of a low-spin Fe(III) with delta g = 0.22, leads to a form displaying different spectral properties (lambda = 710 nm, delta g = 0.31). Butyric acid also acts as a competitive inhibitor of nitrile-hydratase-catalyzed hydration of acrylonitrile with a Ki value of 0.9 mM. Formation of the complex between the enzyme and butyric acid is highly dependent on the concentration of the latter and on pH. When stored with high levels of butyric acid, nitrile hydratase is completely inactive. The active uncomplexed enzyme is restored under the high dilution conditions used for the enzymatic assays, while the complexed form is favored at acidic pH and is not formed at pH above 8. Furthermore, the inhibitory potency of butyric acid decreases upon increasing pH (IC50 increases from 0.8 mM at pH 6.2 to 12 mM at pH 8.2). These data show that nitrile hydratase interacts with the acid form of butyric acid with a high affinity (Ki' approximately 4 microM at pH 7.2). At pH < 3, the visible spectrum of the enzyme disappears, presumably because of demetallation, whereas that of the complex exhibits a charge-transfer band shifted to 800 nm, the presence of butyric acid preventing nitrile hydratase from demetallation. Other linear carboxylic acids such as valeric and hexanoic acids behave similarly; they act as inhibitors of nitrile hydratase and protect the enzyme during storage. A structure of the nitrile hydratase active site interacting with butyric acid is tentatively proposed in which the latter is hydrogen-bonded to the Fe(III)-OH moiety. This interaction between butyric acid and nitrile hydratase should be considered when deducing the nature of nitrile hydratase active site and mechanisms, from spectral and enzymatic data, since most results published previously have been obtained on nitrile hydratase containing large amounts of butyric acid and interpreted without taking into account the presence of this acid in the active site.

Acrylonitrile↗
PubMed1996

[Plasticity of the myocardium in pediatric cardiology].

The phenotypic adaptation of the myocardium to mechanical overload is a well known concept. The changes that occur into the myocardial structure in heart failure lead to new therapeutical approaches, particularly the use of ACE inhibitors in the treatment of dilated cardiomyopathies in order to prevent myocardial remodeling. In the hypoplastic left heart syndrome or in pulmonary atresia-intact septum, the pathogenetic process is supposed to be abnormal intra-cardiac blood flow during fetal life inducing abnormal cardiac remodeling. When the left ventricle ejects into the pulmonary circulation (double discordance, atrial repair of transposition of the great arteries), the surgical repair that consists to replace the left ventricule in the systemic circuit is based on the concept of ventricular remodeling and plasticity.

Adaptation, Biological↗
PubMed1996

The multi-track angiography catheter: a new tool for complex catheterisation in congenital heart disease.

OBJECTIVE: To develop a simple and versatile catheter system for complex cardiac catheterisation because angiography and pressure measurements during diagnostic and interventional cardiac catheterisation are often unsatisfactory. METHODS: The Multi-Track Angio catheter system is a single lumen side-hole catheter with a short distal extension containing a lumen for a standard guidewire. The catheter is introduced over a previously placed guidewire running through this distal extension. It can then be manipulated within the heart by sliding along the guidewire. The tip of the catheter is always stabilised by the guidewire. This stability enhances angiography and pressure recordings. RESULTS: The Multi-Track Angio catheter system was used in 84 patients (age 1 day-20 years). Thirty one procedures were diagnostic and 53 interventional. The decision to use the Multi-Track Angio catheter was based on three criteria: firstly, unsatisfactory angiography obtained with conventional equipment; secondly, difficult catheter course requiring use of a guidewire; and thirdly, requirement for angiography and pressure recordings during interventional procedures. No complications were encountered. High quality angiography could be performed in all cases without catheter recoil. CONCLUSIONS: The Multi-Track Angio catheter system allows for high quality angiography and pressure recordings during diagnostic and interventional cardiac catheterisation. The advantage of the system is that both angiography and pressure recordings can be performed repeatedly from stable catheter positions using a previously placed guidewire. This reduces the need for guidewire manipulations or catheter exchanges and decreases procedure time and the risk of complications.

Adolescent↗
PubMed1996

Long-term fate of the coronary arteries after the arterial switch operation in newborns with transposition of the great arteries.

OBJECTIVE: Concern continues to be expressed about the long-term impact of coronary artery translocation after the arterial switch operation for transposition of the great arteries. This study was conducted to determine the prevalence of obstructions of the translocated coronary arteries by the use of selective coronary artery angiography. METHODS AND RESULTS: 64 children (mean age 7.6 (SD) 1.5 years) who had survived an arterial switch operation underwent evaluation. They had been operated on by one surgeon and they were followed up by a single hospital. Selective coronary artery angiography was possible in 58 patients. Five patients showed occlusion or stenosis of a coronary artery: one occlusion and two stenoses of the left coronary trunk, two occlusions of the circumflex artery. The prevalence of late coronary artery complications was 7.8 (SD) 6.6% (95% CI 1.2 to -14.4%). The three patients with occlusion of one coronary artery had perioperative ischaemic complications, with associated electrocardiogram evidence of ischaemia and left ventricular dysfunction with mitral valve insufficiency. Both patients with stenosis of the left main coronary artery trunk did not have any evidence of an anomaly before catheterisation. CONCLUSIONS: The prevalence of the late coronary artery complications after an arterial switch operation was low in this series. This accords with the view that the arterial switch operation remains the preferred treatment for such patients. Screening for late coronary artery patency should be done by using selective coronary artery angiography, because even patients who remain symptom free can have coronary artery anomalies.

Coronary Angiography↗
PubMed1996

Pulmonary balloon valvuloplasty in the palliation of complex cyanotic congenital heart disease.

OBJECTIVE: To assess the value of pulmonary balloon valvuloplasty in the interim palliation of complex congenital heart disease and pulmonary stenosis in children, who often require numerous palliative operations before definitive surgical repair. METHODS: Evaluation of pulmonary balloon valvuloplasty procedures performed over a five year period in 18 patients (age 8 days--29 years; mean 5.5 years) with complex cyanotic congenital heart disease. RESULTS: After pulmonary balloon valvuloplasty oxygen saturation increased from a mean (SD) of 69 (7.5)% to 83 (7.0)% (P < 0.001). Mean pulmonary artery pressure increased from a mean (SD) of 11.3 (3.8) mm Hg to 15.7 (3.9) mm Hg (P < 0.001). Transient complete atrioventricular block occurred in one patient. No other complications were encountered. In 5 patients (28%) there was an inadequate improvement in cyanosis compared with pre-procedure values (72 (4.7)% v 66 (8.1)%). Reasons for failure were increasing infundibular stenosis in three and inadequate mixing in one child. In 13 patients (72%) pulmonary balloon valvuloplasty gave adequate interim palliation over a mean follow up of 1.1 (1.3) years. Oxygen saturation was 81 (5.6)% at last follow up compared with 70 (7.3)% before pulmonary balloon valvuloplasty (P < 0.001). CONCLUSION: Pulmonary balloon valvuloplasty is a safe and effective technique in the palliation of patients with complex cyanotic congenital heart disease associated with pulmonary valve stenosis.

Adolescent↗
PubMed1996

Thymosin beta4, inhibitor for normal hematopoietic progenitor cells.

Thymosin beta4 (Tbeta4), isolated from the calf thymus fraction 5, has a ubiquitous localization and plays a pleiotropic role in both the immune and nonimmune systems. Because it contains at its N-terminal end the sequence of a known inhibitor of hematopoiesis, the acetylated tetrapeptide Ac-N-Ser-Asp-Lys-Pro (AcSDKP, Goralatide), we have assayed Tbeta4 on human hematopoietic cells. We demonstrate that it inhibits normal bone marrow progenitor cell growth; indeed, it decreased the growth of both granulo-macrophagic and erythroid progenitors and reduces their percentage in S phase. Furthermore, we show that Tbeta4 reduces both the clonogenicity and the cell proliferation of purified CD34+ cells induced by a combination of seven growth factors. Although Tbeta4's inhibitory effect is very similar to that of AcSDKP, we demonstrate, using neutralizing antibodies and a truncated form of Tbeta4 devoid of the AcSDKP sequence, that the inhibitory effect of Tbeta4 is not mediated by the sequence AcSDKP. These data indicate that Tbeta4 is a novel inhibitor for human normal hematopoietic progenitors.

Amino Acid Sequence↗
PubMed1996

[Cardiac MIBG imaging: a new marker for myocardial function in children?].

MIBG cardiac imaging is a non-invasive procedure of studying neuronal recapture of noradrenaline. In adult cardiomyopathy, abnormal results are observed earlier than the increase in circulating catecholamines and constitute a reliable prognostic indicator of the disease. The authors assessed this technique in children with severe cardiac dysfunction in whom the evaluation of ventricular pump function was of primordial importance for the therapeutic decision. Twenty-eight patients aged 3 months to 20 years (average 6.4 +/- 5.8 years) were included in the study. Twenty had hypokinetic dilated cardiomyopathies: with respect to the normal values in adults MIGBG uptake was reduced in all cases. This alteration was correlated with the severity of myocardial dysfunction assessed by echocardiography but is was without doubt the expression of another type of physiopathological process. No relationship was observed with the aetiology of the cardiomyopathy. Eight children had a single ventricle treated by cavopulmonary bypass in 7 cases and by pulmonary artery banding in the other case: MIBG imaging did not allow assessment of myocardial function in these patients probably because the cavopulmonary bypass denervated the heart and thereby changed MIBG uptake independently of the cardiac function. These preliminary results are encouraging and should lead to the adoption of MIBG imaging as one of the key investigations in the functional evaluation of childhood cardiomyopathy and perhaps as an important parameter in the decision of transplantation in this indication.

3-Iodobenzylguanidine↗
PubMed1996

[Treatment and prognosis of tachyarrhythmia after atrial surgical repair of transposition of great vessels].

The Mustard and Senning procedures may be complicated by atrial tachyarrhythmias. In order to determine their prognosis, the authors undertook a review of the 288 patients operated and followed up in their department. Thirty-six (12.5%) had documented atrial tachycardias. In 13 cases, Holter monitoring showed bursts of atrial tachycardia. In the other 23 cases, the tachycardia was sustained and often caused severe symptoms (syncope). Reduction of the sustained forms was obtained by rapid atrial pacing, cardioversion or amiodarone therapy. After restoration of sinus rhythm, several therapeutic protocols were used, often in the same patient: abstention, leading to 5 recurrences in 6 cases; treatment with betablockers in 12 patients with well tolerated or exercise-induced atrial tachycardia with 11 successes; amiodarone, with 4 relapses out of 5 when the dosage was less than 200 mg/m2/day and 13 successes out of 18 when the dosage was 200-250 mg/m2/day. During a follow-up of 1 to 19 years, 6 severe complications (neurological sequellae, cardiac failure), and 6 deaths, were observed. All these patients were poorly controlled and continued to be have tachyarrhythmias. The authors conclude that tachyarrhythmias are neither rare nor always symptomatic, so justifying their systematic investigation. They should be reduced by oral amiodarone or rapid atrial pacing depending on the clinical urgency, never by intravenous antiarrhythmics which can be dangerous. The poor prognosis associated with tachyarrhythmias makes their control essential either with betablockers or good doses of amiodarone, eventually covered by permanent cardiac pacing.

Adolescent↗
PubMed1996

A translocation at 12q2 refines the interval containing the Holt-Oram syndrome 1 gene.

A gene for Holt-Oram syndrome (HOS) has been previously mapped to chromosome 12q2 and designated HOS1. We have identified a HOS patient with a de novo chromosomal rearrangement involving 12q. Detailed cytogenetic analysis of this case reveals three breaks on 12q, and two of these are within the HOS1 interval. By using a combination of chromosome painting and FISH with YACs and cosmids, it has been possible to map these breakpoints within the critical HOS1 interval and thus provide a focus for HOS gene-identification efforts.

Arm↗