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Biomedical subjects

V Poirier

Publications and source records attributed to V Poirier.

At least 19 recordsLinked to original sources
PubMed2004

[Streptococcus pyogenes endocarditis following varicella: a case report].

Although varicella is most often a benign and self-limited disease of childhood, it can be associated with a variety of serious and potential lethal complications. Especially, the incidence of severe infectious complications caused by group A streptococci has been increasing over the last years. We report the case of a previously healthy young boy with an aortic bicuspidy who developed a varicella complicated by endocarditis due to group A streptococcus, and a haemophagocytic syndrome. A favorable outcome was obtained after an early valvular replacement and 6 weeks of intravenous antibiotics.

Chickenpox↗
PubMed2003

Naloxone for shock.

BACKGROUND: There is pre-clinical evidence, involving several animal species, suggesting that opioid peptides play a role in the physiopathology of shock (endotoxic, hypovolemic, cardiogenic, spinal, anaphylactic). Many case reports have suggested that naloxone (an opiate antagonist) might be an effective treatment for shock in humans, but others have not supported such a point of view. This controversy led us to undertake a meta-analysis of the available evidence on the efficacy of naloxone as a treatment measure of shock in humans. OBJECTIVES: To evaluate the effectiveness and safety of naloxone in human shock and to estimate the methodological quality of the clinical trials. SEARCH STRATEGY: Computerized bibliographic search up to December 2002, review of references of all papers found on the subject and contact with primary investigators of eligible studies. SELECTION CRITERIA: Randomized controlled trials evaluating naloxone in human shock, regardless of the patient's age (adult, child or neonate). DATA COLLECTION AND ANALYSIS: Three independent reviewers extracted data on study design, intervention, outcome and methodological quality. MAIN RESULTS: Three independent readers reviewed 80 human publications and selected six clinical trials. Overall agreement on study selection was perfect (concordance: 100%). This meta-analysis includes six studies involving 126 patients with septic, cardiogenic, hemorrhagic or spinal shock. Naloxone therapy was associated with statistically significant hemodynamic improvement (odds ratio 0.24; 95% confidence interval [95%CI] 0.09-0.68). The mean arterial pressure was significantly higher in the naloxone groups than in the placebo groups (weighted mean difference: +9.33 mmHg; 95%CI 7.07-11.59). No heterogeneity was found for this outcome. The death rate was lower in the naloxone group (odds ratio 0.59; 95%CI 0.21-1.67) but this was consistent with the play of chance. A significant heterogeneity for the latter outcome was detected (p<0.05). REVIEWER'S CONCLUSIONS: Naloxone improves blood pressure, especially mean arterial blood pressure. However, the clinical usefulness of naloxone to treat shock remains to be determined, and additional randomized controlled trials are needed to assess its usefulness.

Adult↗
PubMed2001

Clinical characteristics and outcome of patients with invasive pneumococcal disease, Puy-de-Dôme, France, 1994-1998.

A surveillance program for invasive pneumococcal disease was undertaken in Puyde-Dĵme, an administrative district of the region Auvergne in France, from 1 January 1994 to 31 December 1998. A total of 214 cases were identified. The annual incidence of invasive pneumococcal disease increased (P=0.04) from 5.5 in 1994 to 9.3 cases per 10(5) person-years in 1998. The highest incidences were for children <2 years of age (59.2 cases per 10(5) person-years) and for adults > or = 65 years (18 cases per 10(5) person-years). Clinical diagnoses, available in 200 patients, included acute pneumonia (62%), meningitis (10%), sepsis without focus (20%), and others (8%). The most frequent chronic medical conditions of the patients included smoking, alcoholism, cardiovascular and pulmonary diseases, and malignancies. Thirty-one percent of the isolates were nonsusceptible to penicillin. Penicillin resistance (MIC > or = 0.1 mg/l) was more frequent (P=0.02) in cancer patients. The overall case-fatality rate was 21.5%. Risk factors for death were age, sex, and underlying diseases of the patients, along with the severity of illness. These population-based findings should convince clinicians to offer pneumococcal vaccine to patients at high risk for invasive pneumococcal disease, thereby increasing vaccination coverage levels in France.

Adolescent↗
PubMed2001

The Heartmate II: design and development of a fully sealed axial flow left ventricular assist system.

Our group is developing the control and power transmission components required to implement a permanent and fully sealed left ventricular assist system (LVAS). Starting with the percutaneously powered HeartMate II blood pump, our development efforts are focused in the following areas: a complete redesign of the transcutaneous energy transmission system (TETS) to include a rectification network and autonomous voltage regulation within the secondary coil, a hermetically sealed electronics package containing a miniaturized implementation of the existing redundant drive and control electronics with several power-input options, an implanted rechargeable lithium ion battery pack capable of providing up to 1 h of untethered operation, implantable electrical connectors that allow components to be connected after placement in the body or to be replaced if needed, and a radio telemetry subsystem to transmit diagnostic information and to permit remote adjustment of selected parameters.

Electric Power Supplies↗
PubMed1999

Spinal sonography and magnetic resonance imaging in patients with repaired myelomeningocele: comparison of modalities.

The goals of this study were to evaluate the feasibility of using ultrasonography of the spine in the follow-up evaluation of patients with repaired myelomeningocele at birth and to compare sonography with the accepted modality of magnetic resonance imaging. Over a period of 4 years we performed 165 sonographic studies in 101 patients; 107 sonographic studies had MR imaging results for comparison. We collected our data prospectively. The quality of the sonograms was good in 110 of 129 studies, acceptable in 17 of 129, and poor in two of 129. The sonographic examinations failed in 33 of 165 studies (20%). Concordant information was obtained between ultrasonography and magnetic resonance imaging in the following percentage of studies: level of the distal end of the cord in 82%, position of the cord in the canal in 59%, presence of hydromyelia in 63%, cord duplication in 96%, adhesions in 16%, intradural mass in 37%, cord measurements in 85%, and dural sac measurements in 83%. At the lumbosacral level, we saw no cord pulsation in 57% of the studies in patients with cord adhesions and in 20% of those without adhesions. At the lower thoracic level, we saw no pulsation in 35% of the studies in patients with cord adhesions and in 7% of those without adhesions. Postoperative studies of cord release surgery in eight patients showed varied findings. We conclude that in those patients who have a spinal defect or interlaminar space allowing proper visualization of the lumbosacral spinal canal, ultrasound can provide fairly similar information to that obtained with magnetic resonance imaging of that area with no need for sedation and at a reduced cost. Ultrasonography seems more sensitive than magnetic resonance imaging in the detection of cord adhesions, which is particularly relevant in the diagnosis of tethering.

Adolescent↗
PubMed1999

[Management of severe acute asthma in children in pediatric urgent and intensive care units].

Mortality in cases of severe asthma attacks in children is evaluated at 1%. During initial medical care, repeated evaluation of clinical and para-clinical severity criteria constitutes the main therapeutic guide. Emergency care treatment is based mainly on oxygen therapy, bronchodilatory therapy by discontinuous inhalation, and general corticotherapy. Intravenous theophylline treatment is controversial. The response after a few hours should allow a decision to be made [1] to follow up with outpatient treatment (rapid marked improvement), [2] to continue the hospital treatment (stabilization), or [3] to transfer to intensive care (worsening, exhaustion). In the intensive care unit, the treatment is based on continuous intravenous administration of beta 2 mimetics in addition to the above therapies. The objective is to avoid resorting to assisted ventilation. When this proves necessary, it must not be detrimental; controlled alveolar hypoventilation allows dynamic hyper-inflation linked to ventilation to be reduced. Prevention of relapse is indispensable. This requires hospitalization in a specialized care unit after discharge from intensive care.

Adrenal Cortex Hormones↗
PubMed1997

Serum-dependent and cell cycle-dependent expression from a cytomegalovirus-based mammalian expression vector.

Cytomegalovirus-based mammalian expression vectors are widely used to drive the expression of transfected genes in cultured cells. Immunofluorescent staining of the WT1 protein in 3T3 and 293 cell clones, stably transfected with a cyomegalovirus (CMV) expression vector carrying a cDNA coding for the tumour suppressor protein WT1, showed extreme cell to cell variation in the amount of recombinant protein expressed, indicative of cell cycle dependence. This was investigated further by Western blot and FACS analysis which showed that WT1 protein expression was highest in S phase and almost absent in G0/G1. Northern blot analysis of cell clones expressing sense or antisense WT1 cDNAs regulated by the CMV promoter/enhancer showed that RNA expression was also cell cycle-dependent. Western blotting of cells expressing a luciferase reporter gene driven by the CMV promoter/enhancer also showed apparent cell cycle-dependent expression. We further demonstrated that the expression of these gene constructs was serum responsive with a 10-fold increase in expression occurring 2 h after the addition of serum. These results show that the CMV promoter/enhancer system varied in its response to serum and the cell cycle state. Therefore, care must be taken when interpreting any phenotypic alterations (or lack of them) produced in cells transfected with CMV-based expression vectors.

3T3 Cells↗
PubMed1996

Neuronal defects in genotyped dominant megacolon (Dom) mouse embryos, a model for Hirschsprung disease.

Dominant megacolon (Dom) is one of four mutations in the mouse which can produce a phenotype similar to Hirschsprung disease in man. Here, we report that it is possible to take advantage of two microsatellite markers to genotype Dom embryos and to study enteric neuronal development in Dom embryos using whole-mount immunohistochemistry. Dom embryos present a variable defect in the ileo-caecal region, as do embryos of other murine models of Hirschsprung disease.

Animals↗
PubMed1994

Autoregulation of the human WT1 gene promoter.

The human Wilms tumour suppressor gene, WT1, encodes a zinc-finger protein which can function as a transcriptional activator or suppressor. This study reports the analysis of the human WT1 gene promoter, and demonstrates that high levels of WT1 expression lead to autosuppression of the WT1 promoter. Deletion analyses of the promoter region implicate sequences 5' and 3' of the transcriptional start site as being crucial in WT1 autosuppression. Loss or alteration of this function of WT1 may be important in tumourigenesis.

DNA Mutational Analysis↗
PubMed1994

Environmental signals and neural crest cells.

Cell lineage analysis in both the central and peripheral nervous system of vertebrates has revealed that many neural progenitor cells are multipotent. These observations have raised the general issue of when and how such multipotent progenitors generate their various differentiated progeny. The environment of these progenitors controls the cell lineage decisions in the neural crest. This review considers the roles of the environmental signals in the context of the development of several different neural crest-derived lineages.

Animals↗
PubMed1994

Magnetic resonance abnormalities and cardiovascular disease in older adults. The Cardiovascular Health Study.

BACKGROUND AND PURPOSE: Cerebral magnetic resonance imaging often detects abnormalities whose significance is unknown. The prevalence and correlates of findings such as ventricular enlargement, sulcal widening, and increased white matter signal intensity were examined in 303 men and women aged 65 to 95 years participating in a multicenter study of cardiovascular disease. METHODS: Cerebral magnetic resonance imaging was performed and interpreted according to a standard protocol, and findings were correlated with measures of cardiovascular disease and its risk factors. RESULTS: Measures of cerebral atrophy increased with age and were greater in men than in women (each P < .01). Ventricular enlargement and sulcal widening were associated with prior stroke, hypertension, diabetes, and white race (each P < .03). Extent of white matter hyperintensity was associated with age, prior stroke, hypertension, and use of diuretics (each P < .004). On multivariate analysis, age, male gender, white race, and prior stroke retained strong associations with increased ventricular and sulcal scores. After adjustment for age, prior stroke, and other risk factors, white matter hyperintensity was associated with atherosclerosis as measured by increased internal carotid artery thickness on ultrasound. CONCLUSIONS: Cerebral atrophy and white matter hyperintensity are common in the elderly and are associated with age, prior stroke, and known cardiovascular risk factors. Though these findings have been suggested to represent normal aging, their wide variability and associations with cardiovascular disease argue against their inevitability with advancing age and support the need to identify modifiable risk factors for these abnormalities.

Age Factors↗
PubMed1992

Inactivation of the remaining allele of the WT1 gene in a Wilms' tumour from a WAGR patient.

A candidate gene (WT1) has recently been described for the 11p13 tumour-suppressor gene involved in the development of Wilms' tumour. This gene encodes a zinc finger protein which can bind to a specific DNA sequence. We have found a 226 base deletion in the mRNA from a unilateral Wilms' tumour, which would cause a frameshift that completely deletes the zinc finger domain. The tumour developed in a patient suffering from the WAGR syndrome, who had a constitutional 11p13 deletion, and so the 226 base deletion represents the inactivation of the remaining WT1 allele in the tumour. This provides further direct evidence that loss of function of WT1 is an essential step in the development of Wilms' tumour.

Abnormalities, Multiple↗
PubMed1991

Analysis of high PSA N-CAM expression during mammalian spinal cord and peripheral nervous system development.

Using a monoclonal antibody that recognizes specifically a high polysialylated form of N-CAM (high PSA N-CAM), the temporal and spatial expression of this molecule was studied in developing spinal cord and neural crest derivatives of mouse truncal region. Temporal expression was analyzed on immunoblots of spinal cord and dorsal root ganglia (DRGs) extracts microdissected at different developmental stages. Analysis of the ratio of high PSA N-CAM to total N-CAM indicated that sialylation and desialylation are independently regulated from the expression of polypeptide chains of N-CAM. Motoneurons, dorsal root ganglia cells and commissural neurons present a homogeneous distribution of high PSA N-CAMs on both their cell bodies and their neurites. Sialylation of N-CAM can occur in neurons after their aggregation in peripheral ganglia as demonstrated for dorsal root ganglia at E12. Furthermore, peripheral ganglia express different levels of high PSA N-CAM. With in vitro models using mouse neural crest cells, we found that expression of high PSA N-CAM was restricted to cells presenting an early neuronal phenotype, suggesting a common regulation for the expression of high PSA N-CAM molecules, neurofilament proteins and sodium channels. Using perturbation experiments with endoneuraminidase, we confirmed that high PSA N-CAM molecules are involved in fasciculation and neuritic growth when neurons derived from neural crest grow on collagen substrata. However, we demonstrated that these two parameters do not appear to depend on high PSA N-CAM molecules when cells were grown on a fibronectin substratum, indicating the existence of a hierarchy among adhesion molecules.

Animals↗
PubMed1991

A mammalian in vitro model to study gangliogenesis from neural crest cells.

In spite of considerable advances towards understanding lineages derived from neural crest cells using amphibian and avian embryos, the molecular mechanisms involved in the formation of mammalian peripheral ganglia remain largely unknown, mainly because of the lack of experimental systems that will allow their in vitro manipulation. Here, we present a novel mammalian in vitro model permitting to study gangliogenesis from neural crest cells. This model allowed us to manipulate molecules involved in cell-cell interactions. Our data are in favour of the existence of a hierarchy among adhesion molecules.

Animals↗
PubMed1990

Traumatic aneurysm of the superior cerebellar artery: case report and review of the literature.

Less than 10% of the 250 reported cases of traumatic intracranial aneurysms have involved the posterior circulation. Traumatic aneurysms of the superior cerebellar artery are extremely rare, with only three cases previously reported. This is the first report of a traumatic superior cerebellar artery aneurysm in which the diagnosis was suggested by computed tomographic scan. The potential for a good outcome suggests the value of early angiography when the history and diagnostic imaging studies suggest the possibility of a traumatic aneurysm.

Adult↗
PubMed1989

Loss of chromosome 11p alleles in cultured cells derived from Wilms' tumours.

Cell cultures have been produced from five Wilms' tumours. All cultures had a finite lifespan and a pattern of antigen expression which indicated that the cells were derived from the differentiated components of the tumours. No cells showed any of the expected characteristics of the putative Wilms' tumour stem cell. Nevertheless, in both cases where the original tumours showed a loss of heterozygosity at chromosome 11p alleles, the cultured cells also demonstrated a loss of heterozygosity. Thus these cell cultures definitely originated from Wilms' tumour tissue. The results demonstrate that cell cultures can be produced from the differentiated tissues present in Wilms' tumours and that these non-immortal cells show no 'transformed' phenotype, even though they possess the genetic changes present in the original tumour.

Alleles↗
PubMed1988

SV40 transfection of human kidney epithelial cells and stability of chromosome 11.

Simian virus 40 (SV40) transformation has been used in a variety of mammalian cells and has been shown to extend their life span. We therefore decided to apply these results to normal kidney and tumoral cells derived from Wilms' patients. Wilms' tumour, a nephroblastoma which presents in early childhood, has been linked to deletions and rearrangements in chromosome 11. Analysis of gene structure in the 11p13 locus involved in the development of the tumour has been restricted by the very short life-span of the tumoral cells in vitro. We transfected normal kidney WT/NK, tumoral WT/T cells and human foetal kidney HFK cells with 2 SV40-derived plasmids SV3neo (pBR322-SV40-containing neomycin bacterial gene) and SVori- (pMK-origin mutated SV40). We isolated a high number of SV40-transfected cell lines. The efficiency of transfection appeared to be extremely low in WT/T cells compared with HFK and even WT/NK. The life span of the cell lines was increased in relation to their untransfected homologues. However, in all of the cell lines except 3, senescence occurred, after crisis step or not. We looked at different markers associated with SV40 transformation of mammalian cells and specifically with the presence of SV40 T antigen in the cells and its consequences: AIG, tumorigenicity, expression and insertion in genomic DNA of SV40 T antigen. Genetic studies involving karyotypic and restriction fragment length polymorphism (RFLP) analysis demonstrated that, despite a frequent pseudo-diploidy, the cell lines derived have conserved the 11p13 locus.

Antigens, Viral, Tumor↗