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Biomedical subjects

P Lebon

Publications and source records attributed to P Lebon.

At least 19 recordsLinked to original sources
PubMed2006

[Nosocomial rotavirus infections in a pediatric unit: surveillance during four successive winters].

UNLABELLED: The incidence of rotavirus and RSV outbreaks during winter seasons leads to overcrowding of pediatric units in the Paris area, and increases the risk of viral nosocomial infections in hospitalized young infants. OBJECTIVE: The aim of this study was to measure the incidence of rotavirus nosocomial infections in children less than 2 years of age during 4 consecutive winters. METHODS: All infants admitted in the pediatric unit during the winter were prospectively screened for rotavirus with a stools exam. All children with negative stools examination on admission but developing diarrhea after 2 days of hospitalization underwent a new screening test for rotavirus in stools. RESULTS: During the 4 consecutive winters, the global incidence of nosocomial rotavirus infection was 13.9% (12.7 to 15.9%). Asymptomatic carriage of rotavirus was detected in 3% of admitted infants. The risk of nosocomial rotavirus infection increases with young age and the length of hospital stay. CONCLUSION: The incidence of nosocomial rotavirus infections was high in this unit. It is related to overcrowding due to coincidence of diarrhea and bronchiolitis outbreaks in the Paris area and to the young age of hospitalized patients.

Age Factors↗
PubMed2006

Single-stranded RNA viruses inactivate the transcriptional activity of p53 but induce NOXA-dependent apoptosis via post-translational modifications of IRF-1, IRF-3 and CREB.

To characterize the mechanisms underlying apoptosis induced by viral infection, transcriptional activation of genes encoding members of the 'BH3-only' family of proteins was analysed during the course of virus infection. Among these genes, only NOXA is transcriptionally activated by vesicular stomatitis virus (VSV), sendai virus (SV), measles virus, herpes simplex virus, or dsRNA and required for efficient apoptosis of cells. Transcriptional activation of NOXA by VSV or SV is independent of p53, but requires the presence of interferon regulatory factor 1 (IRF-1), IRF-3 and cAMP-responsive element binding protein (CREB). Binding to and transactivation of the NOXA promoter by each of these transcription factors is governed by post-translational modification involving different pathways for each factor. Thus, SV infection activates IRF-3 and CREB by phosphorylation triggered by Toll like receptor 3 signalling, and a pathway involving calcium-independent phopholipase A2, respectively. In addition transactivation induced by IRF-1 during viral infection correlates with a 10 kDa increase in its molecular weight, suggesting a covalent linkage with a previously unknown regulatory polypeptide.

Apoptosis↗
PubMed2005

A second locus for Aicardi-Goutieres syndrome at chromosome 13q14-21.

BACKGROUND: Aicardi-Goutières syndrome (AGS) is an autosomal recessive, early onset encephalopathy characterised by calcification of the basal ganglia, chronic cerebrospinal fluid lymphocytosis, and negative serological investigations for common prenatal infections. AGS may result from a perturbation of interferon alpha metabolism. The disorder is genetically heterogeneous with approximately 50% of families mapping to the first known locus at 3p21 (AGS1). METHODS: A genome-wide scan was performed in 10 families with a clinical diagnosis of AGS in whom linkage to AGS1 had been excluded. Higher density genotyping in regions of interest was also undertaken using the 10 mapping pedigrees and seven additional AGS families. RESULTS: Our results demonstrate significant linkage to a second AGS locus (AGS2) at chromosome 13q14-21 with a maximum multipoint heterogeneity logarithm of the odds (LOD) score of 5.75 at D13S768. The AGS2 locus lies within a 4.7 cM region as defined by a 1 LOD-unit support interval. CONCLUSIONS: We have identified a second AGS disease locus and at least one further locus. As in a number of other conditions, genetic heterogeneity represents a significant obstacle to gene identification in AGS. The localisation of AGS2 represents an important step in this process.

Basal Ganglia Diseases↗
PubMed2005

The natural history of Aicardi-Goutières syndrome: follow-up of 11 Italian patients.

Described are the outcomes of 11 Italian patients with Aicardi-Goutières syndrome. Neurologic symptoms progressed in the first year of life and stabilized by the end of the second year in 10 patients. White matter abnormalities remained stable; cerebral atrophy was stable in four patients and progressive in two. Calcifications increased (in number and size) in two of six patients. Serial CSF and serum interferon-alpha measurements (three patients) showed reduced CSF interferon-alpha levels.

Abnormalities, Multiple↗
PubMed2005

Prenatal diagnosis of Aicardi-Goutières syndrome.

OBJECTIVES: Aicardi-Goutières syndrome is an autosomal recessive neurodegenerative disorder inducing cerebral atrophy, intracerebral calcification and developmental arrest. Diagnosis requires the presence of progressive encephalopathy with clinical onset shortly after birth, typical neuroimaging features associated with a raised blood and cerebrospinal fluid interferon-alpha level.A case of prenatal diagnosis of Aicardi-Goutières syndrome is reported. METHODS: An MRI performed at 26 gestational weeks showed bilateral calcifications and white matter abnormalities, cerebral anomalies typically described in this disease. The fetal blood analysis revealed an increase in interferon-alpha. RESULTS: Therefore, the prenatal diagnosis of Aicardi-Goutières syndrome in this fetus was based on the following facts: the familial background with the affected first child and consanguineous parents, a normal pregnancy and normal fetal growth, cerebral anomalies diagnosed on prenatal ultrasound and cerebral MRI, raised interferon-alpha in the fetal serum and no evidence of any infectious etiology. The autopsy performed postdelivery at 28 1/2 weeks' gestation confirmed the diagnosis of Aicardi-Goutières syndrome. CONCLUSION: To the best of our knowledge, this is the first prenatal diagnosis of this syndrome. Such a diagnosis may prove useful for families at risk as long as genetic screening is not available.

Abnormalities, Multiple↗
PubMed2005

Cerebral thrombotic microangiopathy and antiphospholipid antibodies in Aicardi-Goutieres syndrome--report of two sisters.

Cerebral thrombotic microangiopathy was found at autopsy in one of two sisters with Aicardi-Goutieres syndrome, whereas the other revealed increased serum levels of anticardiolipin IgG antibodies (measured only in the living sister); both typical features of systemic lupus erythematosus. These findings add support to the suggestion that Aicardi-Goutieres syndrome and systemic lupus erythematosus are closely related disorders in which dysregulated production of interferon-alpha might play a crucial role.

Antibodies, Antiphospholipid↗
PubMed2004

Congenital glaucoma and brain stem atrophy as features of Aicardi-Goutières syndrome.

We report on three children from two families with Aicardi-Goutières syndrome. All three had congenital glaucoma. Additionally, neuroimaging demonstrated significant brain stem atrophy in the affected sib-pair. These features have not been previously described in Aicardi-Goutières syndrome and expand the phenotypic spectrum.

Abnormalities, Multiple↗
PubMed2004

[Interferon alpha production in the serum of very young infants after viral infections].

UNLABELLED: IFN-alpha detection is useful in some clinical circumstances, but its use has never been validated in young infants with viral infections. OBJECTIVE: The authors wanted to determine it there was any difference in the assessment of IFN-alpha production between infants under or over six months of age. PATIENTS AND METHOD: A series of 233 children with identified common viral infections who had been assessed for IFN-alpha production was retrospectively analyzed. The viral infections were enteroviral meningitis (n =103), respiratory syncytial virus infections (n =60), and rotavirus gastroenteritis (n =70). Data collected from the group of infants under six months of age (n =105) was compared to that of the older children (n =128). Qualitative and quantitative values of interferon-alpha were determined for each group. RESULTS: Interferon-alpha was detected in very young infants (81.9% of cases) as often as in the older age group (80.3% of cases), for any of the three viral infections (P =0.3-0.63). The mean level of interferon-alpha production detected was not lower in the youngest group, and even higher in the group under six months of age with enteroviral meningitis. CONCLUSION: Interferon-alpha detection in very young infants is efficient and may be useful to differentiate between viral and bacterial infection particularly when the etiological diagnosis appears uncertain.

Age Factors↗
PubMed2004

Aicardi-Goutières syndrome: clinical and neuroradiological findings of 10 new cases.

AIM: To describe the clinical and neuroimaging findings in new cases with Aicardi-Goutières syndrome (AGS) from Egypt. METHODS: Ten patients with progressive encephalopathy, bilateral calcification of the basal ganglia and spastic quadriplegia were described. Feeding difficulties, irritability, unexplained episodic fever and acrocyanosis were also observed. They were diagnosed as AGS after excluding possible non-genetic causes (especially TORCH) and because of the high interferon-alpha (IFN-alpha) level in cerebrospinal fluid (CSF) in two children who underwent this specific investigation. RESULTS: Six patients had postnatal microcephaly. Putamen was by far the most common site of calcification (nine cases) inside the basal ganglia. Calcifications were extended to the white matter, periventricular and cerebellum in three cases. Brain atrophy and/or white matter demyelination were evident in most of the cases. Further, hypogenesis of corpus callosum was detected in two cases; one of them had in addition cerebellar hypoplasia, atrial septal defect (ASD) and horseshoe kidney. To the best of our knowledge, the association of these congenital abnormalities has not been reported before in AGS. Eight families were consanguineous. CONCLUSION: This paper presents variability in both age of onset, clinical picture and neuroimaging findings even in the same family, comprising new congenital abnormalities associated with AGS and subsequently expanding the spectrum of heterogeneity. The observation of familial cases and both affected males and females emphasized the major role of the single gene inheritance.

Abnormalities, Multiple↗
PubMed2003

Herpes simplex encephalitis relapses in children: differentiation of two neurologic entities.

Relapses of herpes simplex encephalitis (HSE) occurring after the completion of antiviral treatment have been reported repeatedly in children. The authors report data on six children who had at least one relapse of HSE. Two different mechanisms may account for these relapses, including viral replication or an immuno-inflammatory process, with different therapeutic attitudes. Relapses with viral replication may reveal host susceptibility to herpes simplex virus infection.

Acyclovir↗
PubMed2003

[Community acquired pneumonia and influenza in children].

UNLABELLED: Children without chronic or serious medical conditions are at increased risk for hospitalization during influenza seasons, mainly with respiratory tract infections. But influenza virus infections frequently remain undiagnosed, even in hospitalized patients. We prospectively studied the rate of concomitant and preceding influenza infections in children hospitalized with a community acquired pneumonia (CAP). POPULATION AND METHODS: All 1-15-year-old children with CAP requiring hospitalization between 1st April 2000 and 2002 had nasopharyngeal aspirate for viruses, immunofluorescence and serologies for respiratory pathogens. The peak of influenza IgG measured by complement fixation (CF) is transient, and a titer of 1/64 or more indicates an acute influenza infection in the preceding weeks. Children with chronic disease were excluded and a control group of patients from outpatient clinic was measured. RESULTS: Among 33 previously healthy children (age 4.9 years, range 1.2-14 years), 8 had a pneumococcal pneumonia, 10 a pneumonia caused by Mycoplasma pneumoniae (MP), 1 by Chlamydia pneumonia, and 8 of unknown origin. In six patients immunofluorescence was positive: Respiratory Syncitial Virus, 2, Adenovirus, 1 and Influenza A, 3 (including a patient with concomitant MP infection). Thirteen of the 33 children (39.4%) had evidence of a recent influenza A infection with CF ab > or = 1/64: with pneumococcal pneumonia, 5/10 with MP pneumonia, 3/8 with unknown origin pneumonia, 9/13 of these previous influenza infections being clinically inapparent. Only 1/30 children of control group (3.3%) had CF ab > or = 1/64. CONCLUSION: In this study, influenza infection is the direct cause of CAP of children in 12% of cases. In other children with CAP, 39.4% of patients had an influenza infection in the preceding weeks which leads to secondary infection caused by Streptococcus pneumoniae or by MP or other pathogens.

Adolescent↗
PubMed2003

[Chickenpox during pregnancy].

Varicella during pregnancy is a rare occurrence because of a high rate of spontaneous immunisation in the population. When a pregnant woman presents a typical rash, maternal complications, mainly respiratory distress, can occur and be life threatening. Fetal complications include two types of consequences. Before 24 weeks of gestation, transplacental transmission is estimated around 6%, with about one third of infected fetuses presenting clinical manifestations. Congenital varicella syndrome includes growth retardation, neurological effects as microcephaly, limbs malposition, lung or bowel hyperechogenicity. But most infected fetuses will not show any anomaly. A very few might develop shingles in the first year of life. Peripartum contamination brings a much higher risk of transmission (around 25%). Neonatal varicella infection can be life threatening for the new born baby, especially if premature. A specific treatment should be started as soon as the contamination is discovered. Zoster during pregnancy does not lead to a risk of fetal infection.

Adult↗
PubMed2003

Cree encephalitis is allelic with Aicardi-Goutiéres syndrome: implications for the pathogenesis of disorders of interferon alpha metabolism.

Aicardi-Goutiéres syndrome (AGS) is an early onset, progressive encephalopathy characterised by calcification of the basal ganglia, white matter abnormalities, and a chronic cerebrospinal fluid (CSF) lymphocytosis. Cree encephalitis shows phenotypic overlap with AGS although the conditions have been considered distinct because of immunological abnormalities observed in Cree encephalitis. We report that levels of interferon alpha (IFN-alpha), a marker of AGS, are raised in Cree encephalitis. Moreover, linkage analysis indicates that the disorders are allelic and refines the AGS1 locus to a 3.47 cM critical interval. Our data show that a CSF lymphocytosis is not necessary for the diagnosis of AGS and strongly suggest that AGS and pseudo-TORCH syndrome are the same disorder. Recognition of immunological dysfunction as part of the AGS phenotype provides further evidence of a primary pathogenic role for abnormal IFN-alpha production in AGS.

Abnormalities, Multiple↗
PubMed2002

[Hospitalization for acute community-acquired rotavirus gastroenteritis: a 4-year survey].

OBJECTIVE: To evaluate the number of hospitalizations due to community-acquired rotavirus acute gastroenteritis in a general pediatric unit during a four-year survey. RESULTS: From January 1997 to December 2000, 725 patients were admitted for acute gastro-enteritis to the general paediatric unit of a Parisian children hospital (nosocomial diarrhoea excluded) and 706 (97.5%) of these patients had had a stool microbiologic examination. Diarrhoea was caused by rotavirus in 359 patients (50.89%) and Salmonella sp in 61 (8.6%). Children and infants hospitalized for rotavirus acute gastroenteritis were younger (26% had three months or less, and 50.03% had six months or less) than in other European studies. CONCLUSION: This study is the first in France reporting a systematic survey of hospitalized gastroenteritis during four years. More than half of hospitalized community-acquired gastroenteritis were due to rotavirus in this Parisian area. The young age of patients should be investigated in other French areas, searching for risk factors and rotavirus strains.

Acute Disease↗
PubMed2002

[Procalcitonin and viral meningitis: reduction of unnecessary antibiotics by measurement during an outbreak].

OBJECTIVE: Viral meningitis are often treated with antibiotics in emergency because routine analysis of CSF is not always efficient for distinguishing between viral and bacterial infection. The aim of the study was to evaluate the usefulness of procalcitonin (PCT) to reduce antibiotic treatments. METHODS AND RESULTS: A blood PCT level < 0.5 ng/mL was prospectively used for the diagnosis of viral origin of meningitis in 58 patients (two months-14 years), in which enterovirus was isolated by culture or PCR during an outbreak (May-June 2000). CSF cells range was 10 to 2800/mL (m: 244), PMN 5 to 2464/mL and CSF proteins range was 0.19 to 0.92 mg/dL (m: 0.37). Seventeen patients received antibiotic therapy in admission. In nine patients, PCT (dosage was routinely measured 3/week) result < 0.5 ng/mL was obtained in 24 h and in 48 h in six: treatment was then stopped and children led hospital. In two patients, PCT was > 1 ng/mL because of bacterial coinfection. CSF and PCT values were similar to those of an already published control group. CONCLUSION: PCT dosage allowed to shorten hospitalization of 4.47 (controls) to 2.06 (patients) days in patients receiving unnecessary antibiotic treatments. During this outbreak, PCT dosage allowed to reduce 40 days of hospitalization.

Adolescent↗
PubMed2002

Real-time PCR quantification of human cytomegalovirus DNA in amniotic fluid samples from mothers with primary infection.

A real-time PCR assay was developed to quantify human cytomegalovirus (HCMV) DNA in amniotic fluid (AF) samples collected from 30 pregnant women with primary HCMV infection as detected either from HCMV-immunoglobulin G (IgG) seroconversion or by the presence of HCMV-specific IgG and IgM associated with a low IgG avidity. Clinical information available for each case included ultrasonographic examination and fetal or newborn outcome. HCMV infection of fetuses or newborns was confirmed for the 30 studied cases. AF samples were subdivided into three groups. In group A (n = 13), fetuses presented major ultrasound abnormalities, and pregnancy was terminated. In group B (n = 13), fetuses had normal ultrasound findings, the pregnancy went to term, and the newborns were asymptomatic at birth. In group C (n = 4), fetuses had no or minor ultrasonographic signs, and pregnancy was terminated. The HCMV DNA load values in AF samples were significantly higher in group A (median, 2.8 x 10(5) genome equivalents [GE]/ml) than in group B (median, 8 x 10(3) GE/ml) (P = 0.014). Our findings suggest that HCMV load level in AF samples correlates with fetal clinical outcome but might also be dependent on other factors, such as the gestational age at the time of AF sampling and the time elapsed since maternal infection.

Amniotic Fluid↗