[Functional imaging of the auditory cortex: role of magnetoencephalography]. / Imagerie fonctionelle du cortex auditif. Place de la magnétoencéphalographie.

We present the different methods for detecting cerebral activity in the auditory cortex. Positron emission tomography (PET) and functional MRI (fMRI) measure such activity indirectly by calculating the blood flow rate or the consumption of oxygen. The direct methods of detection record the electrical or magnetic activity by eletroencephalography (EEG), or magnetoencephalography (MEG), respectively. The aim of this study was to define the role of MEG amongst these different techniques using the data from recordings of evoked magnetic fields in 5 healthy subjects. The localizations demonstrated the tonotopic organization of the auditory cortex, with high-pitched sounds showing a more medial cortical projection than low-pitched sounds. These various techniques are complementary. PET allows a pharmacological study of the cortex, and could be used in patients with cochlear implants. FMRI is non-invasive, and has a high spatial resolution. EEG has an excellent temporal resolution, and EEG recordings do not require major equipment or infrastructure. MEG has a better spatial resolution, with the same temporal resolution, as EEC. MEG is particularly useful in the localization of the cortical generators of middle-latency auditory evoked responses.

Beware of dogs licking ears.

A patient with right-sided chronic purulent otorrhoea developed meningitis due to Pasteurella multocida transmitted by a dog that frequently licked his ear. We suggest that patients with a perforated tympanic membrane should avoid being licked on their ears by animals.

Sensitivity of auditory brainstem response in acoustic neuroma screening.

Auditory brainstem response (ABR) is the reference screening technique for acoustic neuromas, but because of a few false negatives and the increasing performance of magnetic resonance imaging (MRI), its role as the standard method has been questioned. We assessed sensitivity of screening tests in 89 patients with surgically proven acoustic neuromas. Sensitivity of ABR was 92%; 94% for extracanalicular neuromas and 77% for intracanalicular neuromas. For stapedius reflex (SR), sensitivity was 84% and for caloric vestibular response (CVR) 86%. The combined sensitivity of ABR + SR was 97% and of ABR + RS + CVR 98%. For false negatives, the greatest diameter including the intracanalicular portion was always less than 18 mm, with a mean of 15 mm, and none of these tumours reached the brainstem. For patients with unilateral cochleo-vestibular deficit, we propose ABR and SR as first-line screening tests. These tests are repeated at 6 months and at 1 year in the case of normal results. MRI is ordered for patients whose auditory threshold is too low and for those whose ABR or SR results favour retrocochlear disease.

[Extemporaneous anatomo-pathological test in surgery of thyroid cancers. Values and limitations]. / L'examen anatomo-pathologique extemporané dans la chirurgie des cancers thyroïdiens. Intérêts et limites.

We report our experience in surgical treatment of thyroid cancer; 2470 total or partial thyroidectomies were performed for a thyroid nodule, 205 were primitive thyroid carcinoma (8.3%). Intraoperative frozen sections diagnoses were performed in 100% of the patients. In this study, a 100% specificity and 74% sensitivity were found. Data for each histological type were compared with the previous studies. Each false negative macroscopic aspect carcinoma's size, differenciation, plurificality were studied in order to understand the limits of frozen sections diagnoses. The higher rate of false negative was found with small, well differenciated vesicular carcinoma. This study shows that high accuracy of frozen sections diagnoses allows to improve the intraoperative management of thyroid cancer. The high specificity of frozen sections diagnoses strengthens our reliance upon this examination.

[Diving goiter. Apropos of 139 cases]. / Les goitres plongeants. A propos de 139 cas.

Between 1976 and 1994, 139 cases of diving goiter were operated. Hyperthyroidism is a factor in compression. Morbidity is low for surgery for diving goiters, but increases if performed in emergency situations. Cervicotomy was used alone in more than 99% of the cases.

Tracheobronchography and balloon dilatation in acquired neonatal tracheal stenosis.

Between 1988 and 1992, 18 mechanically ventilated newborn babies (mean weight 1300 g and gestational age 30 weeks) presented with deteriorating respiratory failure at a mean age of 29 days. All developed increased oxygen requirements, hypoxic and hypercapnic episodes, and radiological changes of fixed lobar emphysema or recurrent atelectasis which sometimes changed sides from one day to another. Tracheobronchography with iopydol-iopydone was normal in five (27%) cases, but in 13 showed tracheobronchial stenosis localised to the lower trachea (seven cases), to the right main bronchus (three cases), or including the left main bronchus (four cases). Eleven of these 13 patients underwent endoscopy and balloon dilatation of the stenotic area. Five patients died, one before endoscopy, one immediately after endoscopies, and three subsequently with severe bronchopulmonary dysplasia. The other six babies recovered without any sequelae after balloon dilatation.

[Malformation of the internal ear and recurrent meningitis: radio-surgical correlations]. / Malformation de l'oreille interne et méningites à répétition: corrélations radio-chirurgicales.

Authors report one case of bilateral inner ear malformation in a 3 years-old child with congenital sensorineural hearing loss, recurrent meningitis and cerebro-spinal fluid leakage. This anomaly is a pseudo-Mondini's malformation with a meningocele through the oval window and a fistula of C.S.F. of the round window. A close radiological and surgical correlation support some physiopathological hypothesis about fistula between sub arachnoid space and middle ear. Authors discuss the place of high resolution computed tomography in case of congenital sensorineural learning loss.

[Value of ultrasonography in the detection of metastatic cervical lymph nodes]. / Intérêt de l'échographie dans la recherche des adénopathies cervicales métastatiques.

A prospective study of 18 consecutive patients with carcinoma of upper respiratory and digestive tracts is presented. The authors describe the lymph node involvement in these cases. Preoperative ultrasound exploration of the cervical node regions was performed and US findings were compared with obtain by physical examination. Despite the limitations of ultrasonography, the diagnostic and prognostic interest were emphasized. Associated with color doppler, higher specificity and sensibility were noted.

Hormonal study of a human mixed follicular and medullary thyroid carcinoma.

We studied the hormonal secretion of a human mixed follicular and medullary carcinoma. Thyroglobulin (Tg) secretion, especially by large cells and sometimes by small ones, was visualized with immunoenzymatic staining. Calcitonin (CT) was produced by small spindle-shaped cells. Moreover, immunofluorescence double staining performed on the resected thyroid tissue showed the secretion of both Tg and CT in a small number of cells. The cells lost their hormonal secretion after 2 months of culture. Hormonal secretion was modulated by different additives in the medium. Tg secretion was induced when TSH was added to the culture medium; the maximal effect was produced with the addition of 1 mU TSH/ml and 1 microM cortisol, which potentiated the effect of TSH on Tg production. A durable Tg secretion was obtained by embedding the cells in Engelbretch-Hohn-Swarn (EHS) tumour matrix. The CT production was reinduced by the addition of 4 mM Ca2+, 1 microM glucagon and 1 microM cortisol to the culture medium. These findings show that different cells are found in a mixed follicular and medullary carcinoma, some of which can secrete both CT and Tg. They can remain differentiated for a long period after being embedded in EHS tumour matrix with Ca2+ and hormonal components.

[Cell culture in thyroid cancers]. / Cultures cellulaires en carcinologie thyroïdienne.

The authors studied the diagnostic interest of cell cultures in thyroid tumors. They cultivated 10 tumours (4 papillary carcinomas, 5 medullary carcinomas and 1 sarcoma-looking tumour). In 7 cases, cultures yielded nothing more than pathologic examination. Nonetheless the study allowed to detect a double secretion (calcitonin and thyroglobulin) in 2 medullary carcinomas which turned out to be mixed proliferations. It also detected a production of thyroglobulin by the sarcoma. They think that cell cultures may have a diagnostic interest besides pathologic examination, allowing precise study of secretory features of the tumors.

[Fistula of the 4th endo-branchial pouch. Apropos of 4 cases]. / Fistules de la 4e poche endobranchiale. A propos de 4 cas.

The congenital fistula of the piriform sinus is a rare, often overlooked, malformation originating in the branchial pouch. More than 70 observations have been reported in the literature. The authors describe four new cases of documented fistula of the fourth endobrachial pouch. The terminology of these malformations and the different hypotheses concerning the fistular routes is given. The authors discuss their own observations and those reported in the literature in order to better define the clinical diagnosis and the request for complementary examinations for fistulae of the piriform sinus. Surgical exploration is the ultimate diagnostic and therapeutic step.

[Acquired tracheobronchial stenosis of the premature infant under artificial respiration. Value of bronchography and endoscopic balloon dilatation. Apropos of 7 cases]. / Les sténoses trachéo-bronchiques acquises du prématuré ventilé. Intérêt de la bronchographie et de la dilatation endoscopique au ballonnet. A propos de 7 cas.

The authors report about a series of 7 cases of acquired tracheobronchial stenosis in premature infants who were intubated as soon as they were born and ventilated. Two important points can be pointed out: the merits of bedside bronchography, which allows diagnosing the lesions, the merits of balloon dilatation during tracheobronchoscopy on the ENT operating theatre to treat the stenosis. This technique allowed improving ventilation and removing the tube in 6 of 7 cases.

[Use of cultures of human thyroid cells in physiopathology and pharmacotoxicology]. / Utilisation des cultures de cellules thyroïdiennes humaines en physiopathologie et pharmacotoxicologie.

We reconstituted functional follicles from isolated cells, after embedding in a collagen matrix. Therefore we could carry out many investigations. We showed that the cells embedded in collagen reorganized into functional follicles secreting thyroglobulin (Tg) visualised in the intra-follicular compartment, and triiodothyronine (T3) after TSH stimulation. We used these reconstituted follicles for testing several drugs, amiodarone, propranolol and some anaesthetic drugs (thiopental, midazolam and ketamine). We observed that all these drugs inhibited partially or totally, according to the dose administered, the follicular production of Tg and T3. We also found that the follicles reconstituted from thyroid Grave's tissues gave an abnormal secretion of Tg and T3. Finally we created in Rennes a human thyroid model that permits the exploration of pathologic tissues and that may be used in pharmacotoxicology.

[Intrinsic congenital stenoses of the trachea]. / Les sténoses congénitales intrinsèques de la trachée.

The authors report about one case of intrinsic congenital stenosis of the trachea in a newborn. The prognosis of tracheal stenosis in infants is poor, more so when it is congenital and intrinsic, because it is often extensive and associated with other malformations, especially of the right mainstem bronchus and of the right lung. The prognosis of such extensive stenoses, for which surgery constantly resulted in death, has been improved by a new type of tracheoplasty (Kimura-Tsugawa, 1982). However, these children can only be operated with this procedure once they are through intensive care and acute respiratory distress, often in the neonatal period.

[Exchanges of medical students from Rennes/Erlangen-Nuremberg: various considerations on these exchanges within the E.E.C. framework]. / Echanges d'étudiants en médecine Rennes/Erlangen-Nürnberg: de quelques considérations sur ces échanges dans le cadre de la C.E.E.

The current political trends of the European Economic Community (EEC) have made it more desirable than ever before for medical students to be able carry out part of their training in medical schools other than their Faculties of origin. The authors examine successively: 1) The results of 20 years of twinning-between the Medical Schools of Rennes (France) and Nürnberg-Erlangen (W. Germany). A considerable number of syllabuses and examinations are now recognized as equivalent. So far, nearly 500 students have taken advantage of the possibilities of exchanges lasting a few months or even a full University year. 2) The propositions submitted by the Medical Schools of Rennes and Strasbourg have been selected from the 800 presented by EEC Universities as port of the Erasmus programme. For the whole of the EEC, 12 medical projects have been started up since october 1989. Among the other projects accepted were those of Bonn and Hamburg, Ovideo and Valence, Naples and Barri, Dublin, Coïmbra, Brussels, Copenhagen, Leyden, etc. 3) In order to strengthen the North-South axis of the EEC and to widen further the horizons of European medical students (even beyond Europe), the Medical Facilities of Rennes and of Alcalà de Henares (University of Madrid) have just defined syllabus and examination equivalences as Rennes and Erlangen did some twenty years ago.

[Post-traumatic infections of the frontal sinus]. / Infections post-traumatiques du sinus frontal.

Post-traumatic infectious complications of the frontal sinus occur more frequently after multiple fractures than after isolated fractures. The greatest frequency is found with open traumas of the sinus, due to the presence of foreign bodies and to bone and mucosal destruction. Such infectious complications are curatively treated both medically and surgically, to eliminate the bony and mucosal infection and to restore the normal physiology of the frontal sinus. Stress is laid on the preventive treatment, especially on the quality of the initial surgical treatment, either by restoring the sinus with gauging of the nasal-frontal canals, or by eliminating the sinusal function by a canalization which appears preferable to exclusion by obliteration.