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Biomedical subjects

M François

Publications and source records attributed to M François.

At least 19 recordsLinked to original sources
PubMed2000

MR imaging features of acute bilateral renal cortical necrosis.

Bilateral renal cortical necrosis (BRCN) is an uncommon cause of acute renal failure. Kidney biopsy, arteriography, and contrast-enhanced computed tomography (CT) are usually used to diagnose BRCN. However, these methods can have potentially serious side effects. We report two cases in which magnetic resonance imaging (MRI) evidenced characteristic features of BRCN, which were confirmed by histological findings and arteriography and correlated with clinical evolution. In the first case report, the diagnosis of a massive and complete cortical necrosis variety was suggested on MRI that showed a thin rim of low signal intensity along border of kidneys. It was confirmed on kidney biopsy, and the renal function did not recover. The second case is an incomplete form with cortical patchy areas of low signal intensity. In these two patients, MRI helped to establish an early diagnosis of BRCN with characteristic representative findings, without the potential nephrotoxic effects of iodinated contrast that has to be used in CT and arteriography. Kidney biopsy, besides the risks of complications, provides only a parceled analysis of the renal tissue and therefore does not allow any conclusion as to the extension of cortical necrosis. MRI may be of great help for the diagnosis and follow-up of acute renal cortical necrosis.

Adult↗
PubMed2000

[What is the role of tonsillectomy in children?].

Tonsillectomy is mandatory in the case of chronic airway obstruction associated with tonsillar hypertrophy and in the case of a unilateral enlarged tonsil which may be malignant. Tonsillectomy may be indicated in recurrent tonsillitis. More rarely, tonsillectomy is performed in children for tonsil bleeding or chronic tonsillitis. Allergy and bleeding disorders are not a contraindication for tonsillectomy.

Airway Obstruction↗
PubMed2000

Induction of necrosis in human neutrophils by Shigella flexneri requires type III secretion, IpaB and IpaC invasins, and actin polymerization.

Infection by Shigella flexneri is characterized by infiltration of neutrophils in the intestinal mucosa and by a strong inflammatory reaction. Although neutrophils are constitutively programmed to die by apoptosis, we show that isolated human neutrophils undergo necrosis 2 h after infection with virulent S. flexneri strain M90T but not with the virulence plasmid-cured strain BS176. This was demonstrated by the release of azurophil granule proteins concomitant with the release of lactate dehydrogenase (LDH), disruption of the plasma membrane, and absence of DNA fragmentation. Mutants with the mxiD1 gene, coding for an essential component of the secretion type III machinery, or the genes coding for IpaB or IpaC invasins deleted were not cytotoxic. Neutrophil necrosis occurred independently of the bacterial ability to leave phagosomes, and it involved actin polymerization, as the addition of cytochalasin D after phagocytosis of Shigella inhibited the release of LDH. In conclusion, Shigella kills neutrophils by necrosis, a process characterized by the release of tissue-injurious granular proteins. This probably contributes to disruption of the epithelial barrier, leading to the dysentery observed in shigellosis and allowing Shigella to enter its host cells.

Actins↗
PubMed2000

[Direct foreign body footplate trauma: 3 cases].

3 cases of direct foreign body footplate trauma are described in children. A surgical exploration was decided on history, cochleovestibular signs and/or CT abnormalities. Hearing improved in all cases after surgery.

Adolescent↗
PubMed1999

Transnasal endoscopic repair of congenital defects of the skull base in children.

OBJECTIVE: To examine imaging findings and methods of endoscopic treatment of congenital skull base defects in children. DESIGN: Retrospective study and case series. SETTING: Academic tertiary care center. PATIENTS: Four patients (aged 12 and 14 months and 8 and 13 years) were included from 1995 to 1997. Three presented with a nasal glioma, which was recurrent in 1 case. The fourth patient presented with bacterial meningitis due to a spontaneous cerebrospinal fluid leak. Computed tomography and magnetic resonance imaging were used to locate the defect of the skull base. INTERVENTION: Transnasal endoscopic resection of the glioma or the meningocele, with immediate repair of the skull base defects using free mucosal flaps and/or pediculized mucosal flaps and/or conchal cartilage together with fibrin glue and nasal packing during a 3-week period. RESULTS: None of the 4 patients has experienced recurrent cerebrospinal fluid leaks or postoperative meningitis. CONCLUSIONS: The transnasal endoscopic repair of congenital meningoceles is a reliable technique in select pediatric patients. Computed tomography and magnetic resonance imaging provide information that can be used to help the surgical procedure.

Adolescent↗
PubMed1999

Crystallographic and chemical composition of otoconia in the salamander Pleurodeles waltl.

The aim of the present study was to define the morphology and the crystallographic and chemical composition of otoconia in different regions of the inner ear in Pleurodeles waltl (urodele amphibian). The inner ear of adults was microdissected and otoconia were analyzed by scanning electron microscopy (SEM), X-ray diffraction, energy dispersive X-ray (EDX) and transmission electron microscopy. Two types of crystals were detected by SEM. Otoconia had different shapes depending on their location in the membranous labyrinth. One type had a cylindrical body with a triplanar smooth facet at each end, the other ones had either a prismatic shape with flat sides and end faces or a fusiform shape with rounded body and pointed end. The forms corresponded to those previously identified by other authors. These two types of otoconia had different X-ray diffraction patterns. The cylindrical otoconia were calcitic and located in the utricle, the other ones were aragonitic and located in the saccule, lagena and endolymphatic sac. An analysis by EDX indicated that both types of otoconia contained about 95% calcium with trace quantities of sodium, magnesium, phosphorus, sulfur, chlorine and potassium. Trace amounts of strontium was only found in the aragonitic otoconia.

Animals↗
PubMed1999

Appearance and evolution of calcitic and aragonitic otoconia during Pleurodeles waltl development.

The aim of this study is to determine the stages of appearance, morphology, crystallographic structure and chemical composition of otoconia during the inner ear development of an urodele amphibian, Pleurodeles waltl. The first otoconia are detected in the otocyst. Near hatching, calcitic otoconia are polyhedral in the saccule and cylindrical in the utricle. During the following stages, the saccular otoconia agglomerate and constitute a polyhedral calcitic otolith. At larval stage 44, aragonitic fusiform otoconia appear on the otolithic surface. At stage 52, X-ray diffraction analysis shows calcite and aragonite patterns. In adults, all the saccular otoconia are aragonitic. In contrast, the utricular otoconia do not show any modification up to adulthood. In the endolymphatic sac, otoconia appear at stage 45 and in the lagena at stage 49. They remain aragonitic up to adulthood. Energy dispersive X-ray spectroscopy (EDXS) elemental analysis of the otoconia reveals a high quantity of calcium with trace quantities of sodium, magnesium, phosphorus, sulfur, chlorine and potassium. However, magnesium and sulfur have a lower concentration in lagenar aragonitic otoconia than in utricular and saccular calcitic ones. As in adults, trace amounts of strontium are only found in aragonitic otoconia.

Animals↗
PubMed1999

Facial neuromas in children: delayed or immediate surgery?

OBJECTIVE: The objective of this study was to investigate the clinical characteristics and outcome of facial nerve neuromas in children. To date, no specific study has focused on children, and the management of these tumors is not codified. DESIGN AND SETTINGS: A review of case series treated in a tertiary care center of pediatric otolaryngology. SUBJECTS: The treatment and outcomes for 7 children (4 infants and 3 adolescents) were analyzed. RESULTS: Six patients underwent complete removal of tumor and immediate restoration of the nerve continuity. The grade of facial palsy improved in 4 of the 6 children, but did not get better than grade 3 (House classification). The remaining patient was managed conservatively and remained stable clinically and radiologically after 9 years follow-up. CONCLUSIONS: These findings support the reasonable strategy of combining conservative assessment of these slow-growing tumors with regular clinical and radiologic evaluations and radical surgery using various procedures. The choice depends on the age of the child, the extent and growth rate of the tumor, the grade of facial palsy, and the hearing function.

Adolescent↗
PubMed1999

[Surgical management of laryngeal stenosis in children].

Surgical management of children with laryngotracheal stenosis changed recently because of the procedure of single-stage approach. Between January 1992 and April 1997, 101 children underwent surgery for laryngotracheal stenosis in our department: 47 of them had a single stage procedure, and 54 a classic laryngotracheoplasty with stenting with an Aboulker's tube or silastic sheets. The majority of the cases were acquired stenosis (64%) and the others congenital. The degree of stenosis was graded into four categories according to Cotton's classification. Thirty six cases were grade 2, 44 cases were grade 3, 21 cases were grade 4. Subglottic localization of the stenosis was found in 64% of the cases and the mobility of the vocal folds was normal in 60% of the cases. The surgery was considered successful after one procedure when there was a permanent and permeable laryngotracheal lumen (no more than grade 1) not requiring a tracheotomy. Of the 47 single-stage procedures, 38 were successful (81%); of the 54 cases managed with classic methods, 30 were successful (55%). These results and the indications of the different surgical procedures are discussed.

Adolescent↗
PubMed1999

[The value of orbital ultrasonography in ethmoid sinusitis in children].

PURPOSE: To assess the value of orbital sonography (US) compared to CT in the management of children with ethmoid sinusitis. MATERIAL AND METHODS: A total of 13 consecutive patients admitted for non-complicated ethmoid sinusitis (absence of visual or neurological symptoms) were prospectively evaluated at US and CT. RESULTS: Three patients had no evidence of postseptal involvement at US. Ten patients had variable degree of postseptal involvement at US: hypoechoic area or fluid collection in the extraconal fat along the medial orbital wall. Results were confirmed at CT in all patients. CONCLUSION: US is useful to confirm the presence of postseptal involvement in patients with ethmoid sinusitis. Contrary to CT, findings at US remain non-specific as to the nature of involvement. Nonetheless, US is helpful for patient management.

Adipose Tissue↗
PubMed1999

[Hearing status of Robin sequence patients].

OBJECTIVE: To determine wether Robin sequence is a risk factor for conductive and/or sensorineural hearing loss. PATIENTS: 13 children with type III Robin sequence, admitted in our institution between 1984 and 1997 for tracheotomy were enrolled in this retrospective study. METHODS: Each child had several audiological evaluations including subjective and objective methods adapted to their age. Subjective methods were audiometric tests, objective methods were Click Evoqued Otoacoustic Emissions and Auditory Brainstem Response. RESULTS: 3 children had normal hearing, 10 children had a conductive hearing loss caused by middle ear effusion, 4 patients had also a congenital permanent sensorineural evolutive hearing loss. Among the 4 infants with a sensorineural hearing loss, 2 had a polymalformative syndrome, and 2 had an isolated Robin sequence. CONCLUSION: Robin sequence is a risk factor for sensorineural hearing loss and conductive hearing loss. This hearing loss should be assessed as soon as possible after birth by otoscopy, click-evoqued otoacoustic emissions, auditory brainstem response and audiometric tests.

Audiometry, Pure-Tone↗
PubMed1998

Nasal foreign bodies in children.

Between 1994 and 1997, a total of 72 nasal foreign bodies were removed from 68 children (28 girls and 40 boys, including 2 repeats) in the ENT Department at Robert Debré Hospital, Paris. Ages ranged from 1 to 12.5 years (median, 3 years). Two children had bilateral foreign bodies. The unilateral foreign bodies were on the right side in 67.6% of cases. The most frequent objects were plastic objects, beads, paper, cotton and foam. Insertion was witnessed by an adult or reported by the child himself in the majority of cases. The other cases were diagnosed when complications occurred (as seen by persistent rhinorrhea and a foul body odor). All foreign bodies were removed in the consultation room using a hook or nasal forceps.

Child↗
PubMed1998

Modeling and implementing a database on drugs into a hospital intranet.

Our objective was to develop a drug information service, implementing a database on drugs in our university hospitals information system. Thériaque is a database, maintained by a group of pharmacists and physicians, on all the drugs available in France. Before its implementation we modeled its content (chemical classes, active components, excipients, indications, contra-indications, side effects, and so on) according to an object-oriented method. Then we designed HTML pages whose appearance translates the structure of classes of objects of the model. Fields in pages are dynamically fulfilled by the results of queries to a relational database in which information on drugs is stored. This allowed a fast implementation and did not imply to port a client application on the thousands of workstations over the network. The interface provides end-users with an easy-to-use and natural way to access information related to drugs in an internet environment.

Chemistry, Pharmaceutical↗