Biomedical subjects
J Courtois
Publications and source records attributed to J Courtois.
[Odontogenic keratocysts, diagnostic hazards and surgical attitude].
Explore the source record for details and available documents.
The occurrence of negative middle ear pressure in children: an analysis of supposed associated factors.
This study analyzed the occurrence of negative middle ear pressure in various groups of children by comparing them with control groups. A screening procedure recording middle ear pressure and screening audiogram was performed several times throughout the year in an unselected group of 352 seven-year-old children. From about 4000 measurements of middle ear pressure an average value for each child was calculated. By applying thresholds of pathology of -160 mm H2( and -240 mm H2O, the occurrence of pathology in the different groups was analyzed. A medical history of each child was obtained by questionnaires answered by parents, giving information concerning allergy, previous adenoidectomy, previous exposure to respiratory tract infections and the social group of the family. A score of dental caries was obtained in each child. Furthermore, the relationship to antibiotic treatment and the child's use of swimming pools was analyzed, based on single measurements. The use of swimming pools seems to be beneficial to children suffering from a negative middle ear pressure. However, the other variables showed no relationship to negative middle ear pressure. It is concluded that other unknown factors must be involved in the development of negative middle ear pressure and chronic OME in children.
The correlation between negative middle ear pressure and the corresponding conductive hearing loss in children. A 12-month study of 352 unselected 7-year-old children.
An epidemiological study of negative middle ear pressure in children made it possible to test its relationship to conductive hearing loss. About 350 children were subjected to a screening procedure recording audiogram and middle ear pressure five times during a 12-month period. Those children who failed to perceive just one tone or who had a middle ear pressure equal to or worse than -150 mmH2O in one or both ears were referred to the Hearing Clinic for conventional audiometry and middle ear pressure measurement each month. By computing the weighted average of the regressions for each child, a straight linear relationship was found between negative pressure and conductive hearing loss. In addition, a frequency dependence was found, the hearing loss being maximal at about 500 Hz. In general, the study shows that tympanometry is of limited value in predicting hearing loss in a child. The threshold for pathology of about -150 mmH2O, being a predisposing factor in secretory otitis media, corresponds to the upper confidence limit of the normal range of hearing loss found in this series. There is no distinct value of negative pressure that clearly distinguishes between normal and pathological condition, but it is concluded that a middle ear pressure worse than -150 mmH2O should be considered a probable hearing handicap.
How to deal with audiological "cases" as human beings.
Explore the source record for details and available documents.
Observations on the mechanism of phonation investigated by ultraspeed cinefluorography.
Explore the source record for details and available documents.
[Apropos of pancreatic scintigraphy].
Explore the source record for details and available documents.
Contributions of intermolecular interactions between constitutive arabinoxylans to the flaxseeds mucilage properties.
The main fraction (about 75%) of the mucilage extracted from seeds of Linum usitatissimum which consists of arabino-xylans (AX) has been studied in dilute and semidilute regimes by SEC/MALLS analysis and rheology, respectively. It has been found that AX contains 3 populations of about 5 000 000 g mol(-1) (less than 10%), 1 000 000 g mol(-1) (about 40%), and 200 000 g mol(-1) (about 50%). We have also observed a great retention of polymer during the filtration procedure, which is much pronounced as the AX concentration increases. This evidences the presence of large aggregates in the solution. The retention can be greatly diminished if the filtration is conducted under higher temperature. Aggregation could result from the establishment of intermolecular associations via hydrogen bonds. This hypothesis seems to be confirmed by the two higher populations in molar masses which present a random coil conformation consistent with a low degree of branching. Rheological measurements, conducted at 20 g L(-1), have confirmed the association tendency leading to pseudo gels behavior. Viscoelastic properties have been evidenced by time-temperature master curves of dynamic spectra. Such master curves have also been established with addition of chaotropic (i.e., KSCN) and lyotropic (i.e., NaCl) salts. It has been shown that intermolecular associations are greatly diminished under chaotropic salts influence. This has been also confirmed by SEC/MALLS analysis. These results point out the role of hydrogen bonds in the organization of the AX system.
The diagnosis of negative middle ear pressure in children. The accuracy of symptoms and signs assessed by tympanometry.
Over a period of one year, we studied 352 children at random in order to determine whether or not a diagnosis of negative middle ear pressure can be made reliably without using tympanometry. Each child was tested repeatedly by screening audiometry at 20 dB and by tympanometry, and was examined once by otoscopy. Information about upper respiratory tract infections, feelings of oppression in the ears, and the parents' opinion of the child's hearing ability were obtained from questionnaires. Otoscopy correlated poorly with the tympanometry, while screening audiometry and the parents' opinion of the child's hearing ability were more reliable measures. It is concluded that tympanometry is an absolutely necessary tool in the clinical diagnosis of negative middle ear pressure.
[Bronchial specimen collection via transtracheal puncture].
Explore the source record for details and available documents.
[Demonstration of a metabolic property of Rhibozium meliloti usable for its classification].
Fast-growing Rhizobium and Agrobacterium strans were studied for their behaviour towards two carbohydrates (glucose and fructose) according to the following criteria: acidification and soluble exopolysaccharide production by resting cells. R. meliloti and Agrobacterium spp. showed a similar behaviour: in glucose-containing medium, acidification occurred and few exopolysaccharides were produced, whereas in medium supplemented with fructose, a neutral pH was maintained and large amounts of exopolysaccharides were synthesized. Other fast-growing Rhizobium spp. did not acidify these media and produced variable amounts of exopolysacchrides.