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Biomedical subjects

G Roger

Publications and source records attributed to G Roger.

At least 19 recordsLinked to original sources
PubMed2006

Calcium phosphate fibres synthesized from a simulated body fluid.

The biomimetic coating method was used for fabricating calcium phosphate fibres for biomedical applications such as bone defect fillers. Natural cotton substrate was pre-treated with phosphorylation and a Ca(OH)2 saturated solution. The pre-treated samples were then soaked in simulated body fluid (SBF) of two different concentrations, 1.5 times and 5.0 times the ion concentration of blood plasma. The cotton was then burnt out via sintering of the ceramic coating at 950 degrees C, 1050 degrees C, 1150 degrees C, and 1250 degrees C. The results demonstrated that osteoblastic cells were able to cover the entire surface cotton fibres, and the cell coverage appeared to be independent of surface roughness and Ca/P ratio of fibres.

Biocompatible Materials↗
PubMed2006

[Middle ear cholesteatoma].

Cholesteatoma is a serious form of chronic otitis media. The aim of this paper is to present the state of the art of disease management, including recent data from the literature and the authors' derived from their Mentors' teaching, Professor Pierre Roulleau (Paris, France) and Professor Robert Charachon (Grenoble, France). The main recent advances concern the use of cartilage grafts to reconstruct the canal wall and/or tympanic membrane (allowing a significant reduction in residual cholesteatoma) and progress in medical imaging allowing more acute preoperative determination of extension of the cholesteatoma (in order to propose an optimally designed surgical technique) and a less invasive postoperative follow-up.

Cholesteatoma, Middle Ear↗
PubMed2006

[Slide tracheoplasty in congenital tracheal stenosis].

OBJECTIVES: Slide Tracheoplasty has progressively become the gold standard in the management of long-segment tracheal stenosis in children and infants. However, in certain situations this operation might become difficult and others techniques might be preferred. MATERIAL AND METHODS: Five patients, 1 to 6 month old had surgery by our team, for complex tracheal stenosis between 2001 and 2005. Tracheal hypoplasia was considered complex because it was associated to either: an acquired critical stenosis, a cricoid stenosis, a bronchial stenosis, a tracheal bronchus or associated to oesophageal atresia and severe tracheomalacia. All of them have been treated by a modified slide tracheoplasty. RESULTS: The postoperative status required an average of 15 days in ICU, including 8 days of ventilation. Two patients had laryngeal nerve injury. Medium term follow up (27 months) demonstrated no need for re-intervention, good potential growth and normal child activity. CONCLUSIONS: Slide tracheoplasty can provide good results in certain cases of severe and complex tracheal hypoplasia in infants.

Age Factors↗
PubMed2006

[Nasal glial heterotopia: embryological and clinical approaches].

INTRODUCTION: Nasal gliomas or heterotopia are nonhereditary congenital malformations composed of heterotopic neuroglial tissue. They usually present in infancy. Evaluation should include preoperative imaging with CT scan and/or MRI to rule out intracranial extension. There have been several cases reported in which nasal gliomas were misdiagnosed as capillary hemangiomas. The differential diagnosis includes prenasal space developmental impairment, which are nasoethmoidal meningoencephaloceles, nasal dermoid and epidermoid cysts. CASE REPORT: We describe the case of a newborn male infant presenting at birth with a paramedial nasal glioma. An embryological and clinical analysis of nasal gliomas is proposed. DISCUSSION: Nasal glioma is an uncommon congenital lesion presenting as a large panel of midline craniofacial anomalies. The embryological and anatomical origins of nasal gliomas are reviewed. The most known embryological theory was described by Grünwald in 1910 and is called the "prenasal space" theory. This theory is very attractive because of the embryopathogenic continuum proposed among dermoids, gliomas, and encephaloceles. In this article, we discuss major embryological theories on nasal gliomas pathogenesis and propose that while the prenasal space theory can explain the occurrence and the continuum between basal anterior or prenasal encephaloceles and gliomas, it cannot explain the occurrence of craniofacial demoids of the same topography. Better knowledge of embryological mechanisms implicated in the pathogenesis of nasal gliomas can help clinical management of this kind of malformations.

Choristoma↗
PubMed2005

RPGR is mutated in patients with a complex X linked phenotype combining primary ciliary dyskinesia and retinitis pigmentosa.

INTRODUCTION: Primary ciliary dyskinesia (PCD) is a rare disease classically transmitted as an autosomal recessive trait and characterised by recurrent airway infections due to abnormal ciliary structure and function. To date, only two autosomal genes, DNAI1 and DNAH5 encoding axonemal dynein chains, have been shown to cause PCD with defective outer dynein arms. Here, we investigated one non-consanguineous family in which a woman with retinitis pigmentosa (RP) gave birth to two boys with a complex phenotype combining PCD, discovered in early childhood and characterised by partial dynein arm defects, and RP that occurred secondarily. The family history prompted us to search for an X linked gene that could account for both conditions. RESULTS: We found perfect segregation of the disease phenotype with RP3 associated markers (Xp21.1). Analysis of the retinitis pigmentosa GTPase regulator gene (RPGR) located at this locus revealed a mutation (631_IVS6+9del) in the two boys and their mother. As shown by study of RPGR transcripts expressed in nasal epithelial cells, this intragenic deletion, which leads to activation of a cryptic donor splice site, predicts a severely truncated protein. CONCLUSION: These data provide the first clear demonstration of X linked transmission of PCD. This unusual mode of inheritance of PCD in patients with particular phenotypic features (that is, partial dynein arm defects and association with RP), which should modify the current management of families affected by PCD or RP, unveils the importance of RPGR in the proper development of both respiratory ciliary structures and connecting cilia of photoreceptors.

Adolescent↗
PubMed2005

Cochlear implantation in children with internal ear malformations.

OBJECTIVE: To evaluate surgical aspects and results of cochlear implantation in inner ear malformations. STUDY DESIGN: Retrospective cohort study. SETTING: Ear, nose, and throat department of a tertiary referral hospital. PATIENTS: Out of 260 implanted children, 18 (6.9%) had inner ear malformations: complex cochleovestibular malformation (n = 11), common cavity (n = 1), and enlarged vestibular aqueduct (EVA) (n = 6). Deafness was progressive in 12 cases (G1) and congenital in 6 cases (G2). Genetics lead to diagnosis in 12 of 13 cases: PSD mutation (n = 11), Waardenburg syndrome (n = 1), negative (1). Mean age at implant was 7.8 years. Mean follow-up period was 48 months. MAIN OUTCOME MEASURES: Medical and surgical outcomes were reported. Closed (CSW) and open (OSW) set word perception and level of speech production were evaluated each year. The results were compared pre- and postoperatively and between the two groups. RESULTS: Gusher at surgery was observed in 50% of cases, with a persistent leak in one case. No facial injury or infectious complications were observed. At 12 months, 83% of the population had achieved more than 75% recognition in CSW, versus 16% before implant (p = 0.001). After 2 years, 64% of patients had more than 50% recognition in OSW. Good oral language was seen in 76% at 2 years and 100% at 3 years, versus 55% before implant (respectively, p > 0.05 and p = 0.03). At 1 year after implant, 83% of the G1 and 20% of the G2 achieved more than 50% recognition in OSW (p = 0.02). After 24 months, 83% of G1 and 40% of G2 had more than 50% in OSW (p > 0.05). Before implant, 75% in G1 and 0% in G2 had good oral language (p = 0.01). At 1 year, 83% in G1 and 16% in G2 had good oral language (p = 0.02). At 2 years, 100% in G1 and 20% in G2 had good oral language (p = 0.02). One child in G1 had no improvement after implantation. CONCLUSIONS: No major complication was seen. Perceptive and linguistic results were variable and depended on the type of the deafness. In progressive deafness, the perceptive and linguistic result are expected to be good. In congenital deafness, the results are more variable.

Adolescent↗
PubMed2004

Fluorescence-lifetime imaging with a multifocal two-photon microscope.

Two-photon microscopy is a powerful tool for imaging of cells or tissues. However, it presents the drawback of being a laser-scanning technique that involves a long acquisition time for fluorescence-lifetime imaging. Thus it is commonly limited to intensity images that give only indications of the location of fluorophores but do not identify the physicochemical properties and interactions between cells' components. To protect biological samples from experiments that are too long and to provide a more comprehensive spectroscopic tool we have developed a time-resolved multifocal multiphoton microscope. This setup allows us to speed up the acquisition while retaining the possibility of measuring both intensity and lifetime images of the sample.

Equipment Design↗
PubMed2004

Radiosynthesis and pharmacological evaluation of [11C]EMD-95885: a high affinity ligand for NR2B-containing NMDA receptors.

EMD-95885, 6-[3-[4-(4-fluorobenzyl)piperidino]propionyl]-3H-benzoxazol-2-one (1) has been described as a selective antagonist for the NMDA receptors containing NR2B subunits, displaying an IC50 of 3.9 nM for this subtype. EMD-95885 (1) has been synthesized in good overall yield and labelled with carbon-11 ( T1/2 : 20.4 min) at its benzoxazolinone moiety using [11C]phosgene. The pharmacological profile of [11C]EMD-95885 ([11C]-1) was evaluated in vivo in rats with biodistribution studies and brain radioactivity monitored with intracerebral radiosensitive beta-microprobes. The brain uptake of [11C]-1 was homogeneous (0.4-0.6%ID/mL) across the different brain structures studied. This in vivo brain regional distribution of [11C]-1 was not consistent with the known distribution of NR2B subunits. Also as a measure of specificity the hippocampus/cerebellum ratio reached 0.8 throughout the time course of the experiment supporting the lack of specificity. Competition studies with the NR2B prototypic ligand ifenprodil and EMD-95885 (1), 30 min before the radioligand injection, displayed homogeneous reduction of [11C]-1 uptake of 40-60%. Pre-treatment of rats with DTG (sigma ligand), MDL105519 (glycine site antagonist) and MK801 (ion channel blocker) had no inhibitory effect on [11C]-1 uptake. Use of haloperidol as a blocking drug also resulted in a homogeneous inhibition of [11C]-1 uptake by 66-60%, which does not reflect binding to dopamine or sigma receptors. Due to the homogeneous radioligand uptake and inhibition and no measure of cerebral blood flow effects during these blocking studies it is uncertain whether any specific binding is observed. In view of these results, [11C]EMD-95885 ([11C]-1) does not have the required properties for imaging NR2B containing NMDA receptors using positron emission tomography.

Animals↗
PubMed2004

[Vincristine treatment for function- and life-threatening infantile hemangioma].

AIM: To evaluate the efficacy of vincristine treatment for function- and life-threatening hemangiomas. PATIENTS AND METHOD: Nine infants, eight girls and one boy, received vincristine treatment (VCR) for endangering hemangiomas. In six cases, the hemangiomas involved head and neck in a segmental unilateral or bilateral distribution (3/6 also had laryngeal and 2/6 tracheal location causing respiratory distress, 5/6 had eyelid and orbital involvement); one infant had disseminated neonatal hemangiomatosis (skin, liver, kidney); two infants had liver hemangiomas with cardiac failure. VCR was prescribed after failure of high-dosage corticosteroid treatment in six, and of both corticosteroids and interferon alpha 2b (5 months) in one; two infants received VCR as first line treatment. RESULTS: A dosage of 1 mg/m(2) IV injection was delivered, with weekly injections first, and then tapering, increasing the interval between injections, depending on the clinical response. The nine infants received from 5 to 25 injections (average: 16), for a length of treatment of 1.5-8 months (average: 5.5 months). In seven patients a clear clinical response was observed at the end of the first month of treatment, while a slow protracted response was noted in two. Transient mild side effects were present in four patients. DISCUSSION: Corticosteroid treatment, although a worldwide recognized treatment of problematic hemangiomas, cannot always control the growth of alarming hemangiomas. Interferon alpha 2a and 2b have proven a 90% effectiveness: treatment for cortico-resistant, function- and life-threatening, hemangiomas.

Antineoplastic Agents, Phytogenic↗
PubMed2004

[Nasal ciliary investigations for the diagnosis of primary ciliary dyskinesia in children].

Primary ciliary dyskinesia (PCD) is an autosomal recessive disorder, characterized by chronic infections of the upper and lower airways, associated in 50% of cases with situs inversus, therefore, corresponding to Kartagener's syndrome. PCD is suspected on clinical features, including bronchitis, rhinosinusitis and chronic otitis media beginning in early childhood. The recurring infections eventually lead to bronchiectasis. The clinical features of PCD have been ascribed to primary defects in cilia, which lead to impairment of mucociliary clearance. Ciliary investigations looking for abnormalities in ciliary motion and ultrastructure can be easily performed at nasal level. Quantitative ultrastructural study of cilia is performed in cases of abnormal ciliary motion and/or clinical symptoms highly suggestive of PCD. In PCD, all or most of the cilia are abnormal, all bearing the same ultrastructural defects, mainly concerning dynein arms. In older children, the detection of a very low nasal NO output could also be useful for the diagnosis of PCD. As soon as the ciliary investigations are easy to perform at the nasal level, they could help for a better detection of PCD. This strategy could be especially useful in cases of atypical presentations, which are underestimated as a cause of recurrent airway infections. Diagnosis of PCD is important in order to prevent the development of bronchiectasis and to avoid any unnecessary procedure.

Age Factors↗
PubMed2001

Chronic stridor caused by laryngomalacia in children: work of breathing and effects of noninvasive ventilatory assistance.

Breathing pattern, gas exchange, and respiratory effort were assessed in five awake children with chronic stridor caused by laryngomalacia during spontaneous breathing (SB) and noninvasive mechanical ventilation (NIMV). During SB, the youngest children were able to maintain normal gas exchange at the expense of an increased work of breathing as assessed by calculated diaphragmatic pressure-time product (PTPdi), whereas the opposite was observed in the older children. NIMV increased tidal volume, from 8.77 +/- 2.04 ml/kg during SB to 11.67 +/- 2.52 ml/kg during NIMV, p = 0.04, and decreased respiratory rate, from 24.4 +/- 5.6 breaths/ min during SB to 16.6 +/- 0.9 breaths/min during NIMV, p = 0.04. NIMV unloaded the respiratory muscles as reflected by the significant reduction in PTPdi, from a mean value of 541.0 +/- 196.6 cm H(2)O x s x min(-1) during SB to 214.8 +/- 116.0 cm H(2)O x s x min(-1) during NIMV, p = 0.04. Therefore, NIMV successfully relieves the additional load imposed on the respiratory muscles. Long-term home NIMV was provided to a total of 12 children with laryngomalacia (including these five) and was associated with clinical improvement in sleep and growth.

Age Factors↗
PubMed2001

Connexin 26 gene mutations in congenitally deaf children: pitfalls for genetic counseling.

OBJECTIVE: To evaluate difficulties encountered in genetic counseling in deaf children carrying connexin 26 gene (CX26 or GJB2) mutations. DESIGN: Prospective study. SETTING: Outpatients, tertiary referral center. PATIENTS: Ninety-six unrelated deaf children in whom CX26 mutations had been detected consecutively. Children were recruited to a center for genetic counseling for deaf children, and all had congenital deafness, sporadic or familial. RESULTS: In 63 children, deafness was clearly a DFNB1 form with autosomal recessive inheritance: 47 of the 63 were homozygous for the most frequent mutation, the deletion of G at position 35 (35delG); 16 of 63 carried on both alleles of CX26 frameshift or stop mutations, or missense mutations affecting a critical region of the gene. In 33 of 96 children, genetic counseling was difficult: 21 of 33 had a single mutation detected, 11 of 33 had new missense mutations or mutations whose pathogenicity remains debated in the literature, and 1 of 33 had a genotype with both a recessive mutation (35delG) and a mutation acting as a dominant mutation. CONCLUSIONS: Interpretation of results for the molecular diagnosis of mutations in the connexin 26 gene is difficult in almost one third of cases. Close collaboration between geneticists familiar with deafness and otolaryngologists is essential to provide a high standard of genetic advice.

Adult↗
PubMed2001

[Episodic laryngeal dysfunction].

Episodic laryngeal dysfunction (ELD), also known as paradoxical vocal cord dysfunction or laryngeal dyskinesia, is characterized by abnormal closure of the vocal cords during inspiration (and sometimes at the very start of expiration). It can manifest in different ways depending on the patient's age. In the newborn, it is usually associated with stridor restricted to the inspiratory breath following crying, and the natural history is always one of rapid resolution. Occasionally, a more severe form presents with intense dyspnea and marked inspiratory stridor in a baby that usually has extensive gastroesophageal reflux which has not been treated adequately enough to improve the dyspnea or the associated vasovagal attacks. A tracheotomy may be necessary. It is rare for this disease to present between the ages of 2 and 8 years. Thereafter, it may present as a form of pseudo asthma resistant to bronchodilators and anti-inflammatory drugs. The dyspnea can be very severe and lead the family to seek hospital admission, at least during the initial episodes. There is a female preponderance. The key to making the diagnosis is the complete reversibility of the patient's symptoms when they are distracted. Exertion asthma can be mimicked by forms of ELD that occur only by effort (apart from the profile of the lung function tests). There may be significant gastroesophageal reflux. Medical intervention (hospitalization and tracheotomy) must be avoided, treatment being essentially behavioral. Finally, some cases of paradoxical adduction of the vocal cords have been described with the use of neuroleptics, brain stem compression, cortical lesions and, much more rarely, motoneuron disease. This diagnosis requires a high index of suspicion, particularly in patients with asthma whose presentation or clinical course with treatment is atypical.

Age Factors↗
PubMed2001

Abnormal central complex is a marker of severity in the presence of partial ciliary defect.

BACKGROUND: Ciliary ultrastructural defects with total lack of dynein arms (DA) cause abnormal mucociliary function leading to the chronic infections observed in primary ciliary dyskinesia. The role of partial ciliary ultrastructural defects, especially those involving the central complex, and their relationship with respiratory symptoms have been less thoroughly investigated. OBJECTIVE: In a pediatric population with partial ciliary defects, we determined the relationship(s) between ultrastructural findings, ciliary motility, and clinical and functional features, and evaluated the outcome of this population. DESIGN: We analyzed the clinical presentation and pulmonary function of 43 children with chronic bronchitis and partial ultrastructural defects (from 15% to 90%) of their respiratory cilia demonstrated on bronchial biopsies. The study population was divided into 3 groups according to ciliary ultrastructure: the main ultrastructural defect concerned the central complex in 23 patients (CC group), peripheral microtubules in 8 patients (PMT group), and DA in 12 patients (DA group). RESULTS: The percentage of ciliary defects was lower in the PMT group than in the CC and DA groups. Patients in the PMT group had less severe disease with frequent normal ciliary motility. Patients in the CC group had initially a higher incidence of respiratory tract infections, extensive bronchiectasis frequently requiring surgery, and arguments in favor of a congenital origin (high proportion of sibling form). Partial absence of DA, although of congenital origin, was associated with a good prognosis. In all groups, follow-up showed that the functional prognosis remained good with appropriate treatment. CONCLUSIONS: In children with chronic respiratory infections, presence of situs inversus, sibling form, obstructive pulmonary syndrome, or bronchiectasis required ultrastructural analysis, regardless of ciliary motility. Detection of CC abnormalities is a marker of severity and required intensive therapy and close follow-up.

Adolescent↗
PubMed2001

Tracheal dyskinesia associated with midline abnormality: embryological hypotheses and therapeutic implications.

Abnormalities of tracheal rigidity, which may lead to the collapse of the airway during expiration and consequent complications, characterize two groups of disorders: tracheomalacia (weakness of the anterior cartilaginous arc of the trachea) and tracheal dyskinesia (dysfunction of the posterior membranous trachea). Tracheal dyskinesia can either be isolated or associated with a more complex syndrome of malformations: esophageal atresia, tracheoesophageal fistula and laryngotracheal cleft. Although our knowledge of the embryological development of the tracheoesophageal axis remains limited, the existence of these associations suggests that tracheal dyskinesia is of congenital origin. The presentation of three clinical cases demonstrates that the coexistence of a midline malformation and of tracheal dyskinesia complicates the therapeutic management of the first malformation. In particular, the postoperative follow-up is often more difficult, and a long-term tracheostomy is often required (sometimes for several years). However, it must be pointed out that tracheal dyskinesia, even in the associated forms, has a good long-term prognosis, since spontaneous resolution as the child grows up is the rule.

Child, Preschool↗
PubMed2000

Audiophonological results after cochlear implantation in 40 congenitally deaf patients: preliminary results.

The aim of this study is to evaluate the prognostic factors of audiophonological results in cochlear implant in congenitally deaf patients. Between 1991 and 1996. 40 congenitally deaf children underwent cochlear implantation in our department, at an average age of 7 years (median: 5 years). The results of speech therapy were evaluated with a mean follow-up of 2 years and were classified according to four criteria: perception of sound, speech perception, speech production and the level of oral language. For each criterion, a score was established ranging from zero to four. These scores were weighted according to age such that the results before and after implantation only reflected the changes related to the implantation. The prognostic factors for good results were: a good level of oral communication before implantation, residual hearing, progressive deafness and implantation at a young age. On the other hand, poor prognostic factors were: the presence of behavioral disorders and poor communication skills prior to implantation. Overall, the major prognostic factor for a good outcome appeared to be the preoperative level of oral language, even if this was rudimentary.

Adolescent↗