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Biomedical subjects

D Roux

Publications and source records attributed to D Roux.

At least 73 records · Page 4Linked to original sources
PubMed1995

An aquatic toxicological evaluation of fenthion in the context of finch control in South Africa.

Queletox, containing fenthion as active ingredient, is the avicide formulation used in South Africa to control red-billed finches (Quelea quelea). Control measures involve night spraying of roosting areas with a light aircraft. Since roosting areas often include reedbeds along riversides and on islands, proper control is difficult without exposing the aquatic environment to some risk of contamination. This study tested the acute effects of fenthion, in association with the queletox formulation, on the cladocerans Daphnia pulex and Ceriodaphnia dubia and the fish species Poecilia reticulata, Tilapia rendalli, Cyprinus carpio, and Oreochromis mossambicus. The chronic effects of fenthion on D. pulex were evaluated in a 14-day reproduction test. Mean 48-hr LC50 values estimated for D. pulex and C. dubia were 1.30 and 1.72 micrograms liter-1 respectively. For the fish estimated 96-hr LC50 values were as follows: 2.12 (P. reticulata), 2.53 (C. carpio), 2.92 (T. rendalli) and 1.71 micrograms liter-1 (O. mossambicus). In the chronic test reproduction of the exposed population was stimulated at the lowest two fenthion concentrations (0.1 and 0.6 ng liter-1), while a reproductive impairment was recorded at concentrations varying from 1 to 10 ng liter-1. Concentrations of fenthion measured in dams after spraying are given to indicate the levels of contamination that may occur. QSAR was used to estimate the toxicity of some fenthion metabolites. The results of this study reveal that fenthion, at the concentrations occurring in the environment after aerial spraying, can have marked effects on the survival and reproduction of D. pulex for long periods after spraying.

Animals↗
PubMed1995

New technique for sternal osteosynthesis.

In our department, we have developed a new method for sternal osteosynthesis. This technique uses steel threads and a sternal retractor. The removable valves are removed and placed with a two-pulley device, which allows good osteosynthesis without assistance or effort.

Humans↗
PubMed1995

Reoperation after the arterial switch operation for transposition of the great arteries.

Although most children after an arterial switch operation for transposition of the great arteries have normal development and cardiac function, a few require reoperation. During the last 10 years, 68 of 753 patients who underwent arterial switch operations (9.3%) underwent 75 reoperations. Thirty underwent early reoperation (< 30 days or during the same hospital stay) and 38 underwent late reoperation. Causes for reoperation included pacemaker insertion (n = 5), left diaphragm plication (n = 4), revision for hemostasis (n = 1), mediastinitis (n = 2), superior vena cava thrombosis (n = 9), subvalvular pulmonic stenosis (n = 5), supravalvular pulmonic stenosis (n = 16), residual atrial (n = 2) or ventricular (n = 8) septal defects, isolated mitral valve insufficiency (n = 2), aortic valve insufficiency (either isolated [n = 1] or in association with mitral incompetence [n = 1] or stenosis [n = 1]), left coronary artery ostial stenosis (n = 1), and recurrent aortic (n = 6) or neoaortic (n = 4) aortic coarctation. In all but 27 patients, the residual defects were already present immediately after the completion of the arterial switch operation; however, only patients with critical lesions were reoperated on early. Interventional catheterization procedures were performed when indicated; however, they only postponed inevitable reoperation. Successful relief of superior vena cava thrombosis was achieved by atriojugular bypass grafting in two patients, by early open thrombectomy in six patients, and by direct patch angioplasty of the superior vena cava once. Patch plasty for subvalvular or supravalvular pulmonic stenosis was carried out in 21 patients, septal defect closure was carried out in nine patients, and pulmonary artery banding was performed in one patient with criss-cross atrioventricular relationship and multiple ventricular septal defects. Valve repair was performed in all five patients with either isolated or combined aortic and mitral valve dysfunction. One patient with left coronary ostial stenosis underwent a patch enlargement of this ostium. Recoarctation was repaired by end-to-end anastomosis in eight patients and by a subclavian flap and a patch angioplasty in one patient each. Seven patients underwent a second reoperation for supravalvular pulmonary stenosis (n = 3), mitral valve replacement (n = 1), ventricular septal defect closure (n = 1), and recurrent coarctation (n = 2). There were six intraoperative (8.8%) and two late deaths. All early deaths occurred after early reoperations.(ABSTRACT TRUNCATED AT 400 WORDS)

Aortic Coarctation↗
PubMed1995

[Persistence of spongy myocardium: apropos of a case].

A two and a half year old child was admitted to hospital with peripheral cyanosis. Echocardiography revealed severe dilated cardiomyopathy affecting both ventricles with abnormally hypertrophied and irregular myocardial walls. The pulmonary hypertension was suprasystemic with raised pulmonary resistances. The magnetic resonance imaging and angiography confirmed the diagnosis of persistence of spongy myocardium. This is a rare abnormality due to the persistence of embryonic myocardium with a network of trabeculations and intertrabecular spaces as usually observed during echocardiography. This case is noteworthy because of the biventricular involvement and the absence of associated congenital cardiac malformation. The prognosis is characterised by a high risk of severe cardiovascular complications.

Cardiomyopathies↗
PubMed1995

Adaptive control of therapeutic drug regimens relations between clinical situations: outcomes and simulations using nonlinear dynamic models.

With Bayesian modeling and adaptive control of drug dosage regimens, serum and peripheral drug concentrations can be predicted in clinical situations using linear pharmacokinetic compartmental models (PK). Recently, several pathophysiologic and pharmacodynamic nonlinear models (PD) have been developed. The present report illustrates both their utility and limits for the computation of effects in clinical situations in the setting of actual routine and acute patient care. Patients who received therapy with aminoglycosides or/and vancomycin were selected. For each patient, after estimation of individual pharmacokinetic parameters, the computed outputs of the linear compartmental pharmacokinetic model were used as inputs for 2 different a priori nonlinear dynamic models: 1) the EFFECT modeling program, using a Hill model, and 2) the BACTCIDE program, which is a combination of a simple growth model for the organism and a Hill effect model considering both the microorganism, the antibiotic, and the patient's minimal inhibitory concentration (MIC). The programs (1) and (2) can use as inputs the computed concentrations from any of three compartments: central, peripheral, or a spherical diffusion compartment to compute drug diffusion into endocardial vegetations or abscesses. The EFFECT program can be used alone for the evaluation of drug effects. The BACTCIDE program illustrates differences in activity between concentration-dependent and time-dependent antibiotics. Such nonlinear programs are very sensitive to the MIC values.

Aged↗
PubMed1995

[Carpentier's supra-annular bioprosthesis in aortic position: a mid-term evaluation].

The aim of this study was to assess the medium and long-term results of the Carpentier-Edwards supra-annular (CESA 2650) bioprosthesis. From the end of 1984 to January 1993, 160 patients aged 71.6 +/- 8.6 years underwent aortic valve replacement alone or associated with coronary revascularisation. The postoperative mortality was 11 patients (6.8%): follow-up included 749 patient-years with an average period of 60 +/- 29 months, which was complete in 96% of operated patients. The late mortality was 30 patients (4% patients/year): the actuarial 5 year and 10 year survival was 78.6% and 59.1% respectively (hospital mortality included). The linear complications rates were: major thromboembolism: 1.3% patients/year; structural deterioration: 1.5% patients/year; reoperation: 0.75% patients/year; total morbid/fatal complications: 5% patients/year. Despite the limited follow-up, the authors' analysis confirmed the low rate of structural deterioration requiring reoperation, especially in patients over 70 years of age in whom there were no cases of reoperation at 9 years. They conclude that the medium-term results of the CESA 2650 bioprosthesis are comparable to those of first generation porcine bioprostheses: the absence of reoperation related to valve complications in the over 70s during the study period suggests that this is the replacement of choice in this category of patients.

Actuarial Analysis↗
PubMed1995

[Prenatal diagnosis of a hydrothorax secondary to an extralobar pulmonary sequestration].

A case of antenatal hydrothorax was observed. The aetiology could not be determined before birth. At birth an extra-lobe lung sequestation was treated surgically after 3 weeks in the intensive care unit. The surgical cure was successful with no sequellae. This favourable outcome is unusual in this type of pathology and can be explained by the fact that the sequestration was isolated in a fetus with only minimal anasarca. Indications for prenatal pleural drainage are discussed.

Adult↗
PubMed1994

Pulmonary circulation evaluation before cavopulmonary connections: the cavopulmonary bypass.

The outcome of Fontan-type procedures is dependent on several risk factors, among which pulmonary vascular resistances (PVRs) are an important component. Preoperative calculation of PVR entails several potential sources of error, particularly in patients with pulmonary atresia or multiple sources of pulmonary blood flow. In an attempt to develop a reliable test that accurately assesses the hemodynamic patterns of the pulmonary vascular bed before a Fontan procedure, a simulation of Fontan-type circulation was achieved in 13 patients by a partial cardiopulmonary bypass between the main pulmonary artery and both venae cavae (cavopulmonary bypass). During cavopulmonary bypass, pressures and resistances were recorded. Immediately after cavopulmonary bypass, the circulation was converted to standard cardiopulmonary bypass and the cavopulmonary connection was carried out. Preoperative pulmonary vascular resistance indexes were assessed roughly by the arteriovenous oxygen difference in systemic and pulmonary beds. There was no correlation between preoperative and perioperative calculations of pulmonary vascular resistance indexes (r = 0.24; p = not significant). Hemodynamic data available for all patients then were correlated to the early postoperative outcome assessed by a subjective four-point scale. A positive, significant correlation was found with intraoperative PVR (r = 0.90; p < 0.001), indexed PVR (r = 0.90; p < 0.001), and the pulmonary to systemic vascular resistance ratio (r = 0.98; p < 0.0001). Two of 13 patients had a 4-mm fenestration in the atrial baffle. No mortality or morbidity was related to the procedure. The absolute values of PVR and pulmonary vascular resistance indexes were strikingly higher than generally admitted for this type of procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Biometric analysis of tooth migration after approximal contact removal in the rat.

Nineteen 8-week-old female Sprague-Dawley rats were used to observe macroscopically the direction of tooth movements following removal of approximal contacts. In 10 rats, under anaesthesia, approximal contact between the second and third right maxillary molars (M2-M3) was removed by grinding. These animals and a control group of nine rats were housed with normal diet and water ad libitum for 7 weeks. After killing, the skulls of all animals were removed, dried, and fixed in a standardized position on a Horsley-Clarke type stereotaxic frame. Using a micromanipulator graduated to 1/100 mm and mobile in three orthogonal directions, distances between the teeth (M1 or M3) and some bone structures that served as landmarks were measured. These measurements showed the direction of tooth movements in the experimental approximal space. After statistical analysis of the data, the results showed that the approximal space between M2 and M3 was closed by both a distal drift of M1-M2 and a mesial migration of M3. It was concluded that, in the rat, a mesial drift exists that can be induced by the loss of approximal contact. This movement is distinct from the distal physiological dental migration classically described in histological studies.

Animals↗
PubMed1994

Surgery for tetralogy of Fallot at less than six months of age.

Absence of consensus persists regarding the optimal procedure and timing for the surgical treatment of young infants with symptomatic tetralogy of Fallot. From 1987 through 1992, 56 patients with tetralogy of Fallot were operated on at less than 6 months of age. Forty-one patients (median age 2.9 months) underwent primary repair and 15 (median age 2.4 months) underwent initial palliation. Mean follow-up was 24.2 +/- 16.4 months. No strict protocol was used but patients who received initial palliation were younger, had a smaller pulmonary arterial tree, or had anomalous coronary artery. Two patients died (overall mortality 3.6%; 95% confidence limits 0% to 11%), one after initial palliation (6.7%), and one after primary repair (2.4%) (P = 0.47). Eight of the 15 patients who received initial palliation underwent repair and had an increase in pulmonary anulus size at the time of definitive repair (mean difference Z-value = 2.2 +/- 1.6 standard deviation; p = 0.006). Transannular patch was required in 50% of patients who underwent repair (56% among patients having primary repair versus 13% for patients having initial palliation; P = 0.03). Five patients underwent reoperation. Early primary repair of symptomatic tetralogy of Fallot was achieved with a low mortality rate and is the preferred protocol. Initial palliation remains indicated in case of associated cardiac anomaly, very low weight, or severely hypoplastic pulmonary artery tree.

Age Factors↗
PubMed1994

[Changes in myocardial beta adrenergic receptors in left ventricular hypertrophy caused by barometric and volumetric overloads].

While most prior studies examined late stages of heart failure, we determined initial changes of beta-adrenergic receptors (beta-AR) during left ventricular chronic volume and pressure overload. We investigated right auricular (RA) and left ventricular (LV) beta-AR density (Bmax, fmoles/mg protein) and beta 1-AR percentage in two groups of patients undergoing valve replacement without LV systolic dysfunction (LV ejection fraction > or = 60%), with normal plasma catecholamine levels and echocardiography LV hypertrophy. These results were compared with the values of a control group, composed by 8 patients with mitral stenosis and 5 cardiac transplant donors, and the values of 5 patients undergoing heart transplantation because of end-stage idiopathic dilated cardiomyopathy. These results show that, before alteration of LV systolic function occurs, left ventricular chronic overload induces a selective down-regulation of LV beta 1-AR compensated by an increase in beta 2-AR. These variations may be due to LV hypertrophy induced by volume or pressure overload.

Catecholamines↗
PubMed1994

[Lethal hydrops fetalis secondary to an umbilical cord hemangioma].

We report an umbilical cord hemangioma associated with an hydrops fetalis and detected by ultrasonography at 21 week's gestation. Because of the fetal distress, a caesarean section was performed at 28 weeks'. The infant died soon after birth despite resuscitation. The post-mortem examination showed an extensive accumulation of serous fluid in the fetal tissues and the body cavities, and major pulmonary hypoplasia. The umbilical cord contained a grossly fusiform tumor which fulfilled the pathological criteria of an umbilical cord hemangioma. Umbilical cord hemangiomas are very unusual tumors and are rarely associated with a fetal hydrops. This tumor is a cause of increased maternal serum and amniotic fluid alpha-foetoprotein levels. Although it is usually isolated, it is imperative to search for associated malformations or angiomas that may clinically manifest later.

Fatal Outcome↗