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F Leclerc

Publications and source records attributed to F Leclerc.

At least 37 records · Page 2Linked to original sources
PubMed1994

A three-dimensional model of the Rev-binding element of HIV-1 derived from analyses of aptamers.

Coordinated variations in the sequence of the Rev-binding element of HIV-1, identified by in vitro genetic selections, have been used as distance and conformational constraints for molecular modelling. Three-dimensional models of the wild-type Rev-binding element and several, evolved RNA ligands (aptamers) have been constructed. These models demonstrate that non-Watson-Crick pairings open the major groove allowing access of an alpha-helical peptide from Rev, and explain why some selected RNA sequences can bind Rev more tightly than others.

Base Composition↗
PubMed1994

[Treatment with intermittent high dosage corticotherapy in chronic interstitial pneumonia in an infant. A case report].

Chronic interstitial pneumonia (PIC) are rare in infants. We report a case of an infant who presented with a chronic interstitial pneumonia following an infection with a respiratory syncytial virus. The diagnosis was confirmed histologically (open lung biopsy). The failure of oral steroid therapy (Prednisolone 2 mg/kg/day) led to the use of boluses of methylprednisone (30 mg/kg/day, daily for three days in three series one month apart). The treatment led to a progressive improvement and thirty months after the last bolus the respiratory examination was normal as was the radiology. The efficacy of bolus steroid therapy observed by other authors should be confirmed in multicentre trials using surgical biopsy to precise the pulmonary lesions.

Administration, Oral↗
PubMed1993

Modelling velocity profiles of rapid movements: a comparative study.

In this paper we compare 23 different models that can be used to describe the asymmetric bell-shaped velocity profiles of rapid-aimed movements. The comparison is performed with the help of an analysis-by-synthesis experiment over a database of 1052 straight lines produced by nine human subjects. For each line and for each model, a set of parameters is extracted that minimizes the error between the original and the reconstructed data. Performance analysis on the basis of the mean-square-error clearly reflects the superiority of the support-bounded lognormal model to globally describe the velocity profile characterizing rapid movements.

Biomechanical Phenomena↗
PubMed1993

Sudden death revealing Chiari type 1 malformation in two children.

We report the first two fatal cases of sudden unprovoked cardiorespiratory arrest in children with previously undiagnosed Arnold-Chiari type 1 malformation. This diagnosis should be considered in children with unexplained cardiorespiratory arrest. The risk of sudden death in Arnold-Chiari type 1 malformation reinforces the indication for early neurosurgical procedure.

Adolescent↗
PubMed1992

Respiratory mechanics in mechanically ventilated newborns: a comparison between passive inflation and occlusion methods.

A passive inflation method was described for measuring total respiratory elastance and resistance during mechanical ventilation in adult patients (Rossi et al., J Appl Physiol 58:1849, 1985). We applied this method to preterm and full-term mechanically ventilated newborn infants and we compared the results with those obtained by the occlusion method. We performed 37 tests in 16 newborn infants (B.W. 880-4,500 g; G.A. 28-42 weeks), between 1 and 45 days of postnatal age, ventilated with a Servo Ventilator 900C, set in controlled-volume mode. Flow was measured through a pneumotachograph inserted between the endotracheal tube (ETT) and the breathing circuit, tidal volume by integration of flow and airway pressure directly at the airway opening. Flow, volume, and pressure were recorded on an X/Y plotter to obtain pressure-volume (P/V), flow-volume (V/V) loops, and pressure-time curves. Occlusion was performed by using the end-inspiratory and the end-expiratory pause buttons of the ventilator. Analysis of P/V and V/V loops provided respiratory system compliance (Crs, infl.), resistance (Rrs, infl.), and "intrinsic positive end-expiratory pressure" (PEEPi, infl.). These values were compared with Crs, occl., Rrs, occl., and PEEPi, occl. measured by the occlusion method. The measurements were well correlated (Crs, infl./Crs, occl.: r = 0.90; Rrs, infl./Rrs, occl.: r = 0.91; PEEPi, infl./PEEPi, occl.: r = 0.91). Rrs, infl./Rrs, occl. and PEEPi, infl./PEEPi, occl. did not differ significantly. However, Crs, occl. was 15% higher than Crs, infl. (P less than 0.01). The passive inflation method is simple to use and well tolerated in preterm and full-term ventilated newborn infants, it provides accurate results, and can be a good alternative to occlusion methods. It requires, however, a constant inflation flow and adaptation to the ventilator.

Airway Resistance↗
PubMed1992

Protein C and S deficiency in severe infectious purpura of children: a collaborative study of 40 cases.

We studied, in 40 children (mean age: 52 months) with severe infectious purpura, the relationships between protein C (PC) and protein S (PS) levels, and shock, disseminated intravascular coagulation (DIC) and outcome. We determined, on admission, PC antigen (ELISA) and activity (chromogenic test), and total PS (ELISA). Results were expressed as % of normal adult values. Statistical analysis was performed with SAS. Thirty children were in shock, 20 had DIC. All children with DIC, and 10 without DIC were in shock. Of 20 children who were in shock and had DIC, 7 died and 3 had an amputation. PC antigen was significantly decreased in shock children (p less than 0.05), in children with DIC (p less than 0.0005), and in non-survivors (p less than 0.05). PC activity was significantly decreased in shock children (p less than 0.05), in children with DIC (p less than 0.0005), and in non-survivors (p less than 0.005). Total PS was not decreased in shock children, but was significantly decreased in children with DIC (p less than 0.005), and in non-survivors (p less than 0.005). We conclude that PC and PS levels were decreased in our children, and that PC levels were significantly decreased in the presence of shock, DIC, and fatal outcome. PC and antithrombin III (AT III) supplementation, should be evaluated in children with severe infectious purpura with shock and DIC.

Adolescent↗
PubMed1992

[Is pericerebral hemorrhage a cause of severe malaise in infants?].

The authors report 7 cases of infants presenting with an apparent life-threatening event associated with acute pericerebral haemorrhage (subarachnoid haemorrhage and/or subdural hematoma) without evidence of traumatism, abuse, or shaking. Clinical characteristics were the same in all cases, including limpness, severe dysautonomic disorders, and pallor; all infants had retinal and pre-retinal haemorrhages. Two infants died; the five survivors have severe neurologic sequelae. The symptoms revealing an infant's pericerebral haemorrhage are usually axial hypotonia and pallor. Traumatism remains the most common aetiology and must be searched for. Non-traumatic aetiologies are unusual and were excluded in these reported cases. The 'shaken baby' syndrome is not the sole aetiology of an apparent spontaneous pericerebral haemorrhage: a slight bump associated with predisposing vascular factors particular to infancy could be involved. When confronted with an apparent life-threatening event associating limpness and pallor, one must consider the diagnosis of pericerebral haemorrhage.

Female↗
PubMed1992

[Striatal involvement with abnormal movements in hemolytic-uremic syndrome].

Two children with hemolytic-uremic syndrome (HUS) presented with alteration of consciousness and severe abnormal movements related to striatal involvement. They required dialysis and controlled ventilation. Steady improvement in neurologic function was seen during the following weeks, and abnormal movements disappeared. It is suggested that the pathogenesis of neurological dysfunction in these two children was related to intracerebral microangiopathy, because neither systemic arterial hypertension, nor metabolic disturbances were present. This hypothesis is supported by the cerebral blood flow study in one patient. Neuropathologic studies of patients with HUS who presented with CNS symptoms showed vascular thromboses within the CNS: CT scan demonstrated multiple small areas of infarction, particularly in the basal ganglia. The prognosis of HUS is generally worsened in case of severe CNS involvement, but abnormal movements may disappear without sequelae.

Brain Diseases↗
PubMed1991

[Long-term outcome of congenital diaphragmatic hernia. A study of 17 patients].

In order to better define the outcome of patients with neonatal congenital diaphragmatic hernia (CDH), 17 patients between 3 and 19 years of age, among 34 survivors from 100 CDH have been re-examined clinically. All had a lung radiography, lung function studies, and radionuclide (Technetium 99m, Xenon 133) lung scans. Three patients suffered from asthma, 2 had recurrent bronchitis, 4 poor tolerance to effort, 3 gastrooesophageal regurgitation leading to endobrachyoesophagus and oesophagitis in one, 3 had scoliosis. Lung scans demonstrated hypoperfusion of the herniated side (less than 40%) in 6 patients. Chest films showed hypovascularisation on the herniated side. Lung function studies, performed in 4 of these 6 patients, showed a restrictive syndrome in 1 patient. Our results confirm those in the literature: perfusion is more altered than ventilation. Chest films at one year of age, completed if necessary by radionuclide lung scans, allow identification of children who have important pulmonary hypoplasia. These children need a regular follow-up: respiratory, digestive and orthopedic complications must be treated in order to preserve the respiratory function in adulthood.

Adolescent↗
PubMed1991

[Hemostasis anomalies and prognosis during severe infectious purpura in children. Retrospective study in 69 cases].

In 69 children with severe infectious purpura (SIP), anomalies of hemostasis on admission were studied retrospectively. Forty-four children presented with disseminated intravascular coagulation (DIC) and 18 with factor VII deficiency +/- thrombocytopenia +/- antithrombin III deficiency. Seven patients were free of hemostasis anomalies. In 5 children, purpura was necrotic on admission, whereas in 9 additional patients skin necrosis occurred subsequently (5 patients with and 4 without DIC). Among the 18 children (26%) who died, 16 were in the DIC group. Factors II and V, fibrinogen and platelet counts were lower in children who died and were correlated with the prognostic score. In the DIC group, however, factor VII + X level was not correlated with the prognostic score and was equally low in fatal and non-fatal cases. Antithrombin III level was markedly decreased in patients who subsequently developed necrosis. These results indicate that factor VII level decreases early in the course of SIP and that consumption of physiologic coagulation inhibitors probably plays a central part in the development of necrotic purpura.

Adolescent↗