Search PubMed⌕ Search

Biomedical subjects

N Deggouj

Publications and source records attributed to N Deggouj.

At least 37 records · Page 2Linked to original sources
PubMed1996

Myelin protein Po as a potential autoantigen in autoimmune inner ear disease.

We have previously shown that a 30,000 Mr protein extracted from guinea pig inner ear tissue is recognized by autoantibodies present in the serum of patients suffering from autoimmune inner ear disease. This protein was localized in the modiolus and in the organ of Corti. We have now identified this protein by a combination of microsequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry of its tryptic peptides. A partial sequence of the protein was thereby determined. These data and 2-dimensional gel electrophoresis followed by immunoblotting experiments showed that the 30,000 Mr inner ear antigen is the major peripheral myelin protein Po. This suggests that protein Po may be an important autoantigen in autoimmune inner ear disease.

Amino Acid Sequence↗
PubMed1996

Guinea pig inner ear antigens: extraction and application to the study of human autoimmune inner ear disease.

In this study, the authors attempted to develop a method of extracting guinea pig inner ear antigens for otoimmunological research, and to investigate the distribution of the antigens in the various structures of the inner ear. The antigens were extracted either from the entire or from various parts of the guinea pig inner ear. These antigens were separated on sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels. Western blot techniques were used to test sera from patients with inner ear disease against guinea pig inner ear protein extracts. It found that the various molecular weight antigens in the inner ear were associated with the different structures of the inner ear. The sera of 37.5% (N = 80) of patients reacted with two bands (30 and 58 kd) of the guinea pig inner ear immunoblots. The 58 kd band was not specific to the inner ear, but instead was also found in the immunoblots of other guinea pig tissues (brain, lung, and liver). This study suggests that the various antigens of interest could be further extracted and purified from the corresponding locations of the inner ear.

Animals↗
PubMed1996

HLA class II-associated genetic susceptibility in idiopathic progressive sensorineural hearing loss.

To investigate the association between genes in the major histocompatibility complex and inner ear disease susceptibility at the DNA level, high-resolution genotyping for HLA class II (HLA-DR, -DQ, -DP) was performed by polymerase chain reaction-sequence-specific oligonucleotide reverse dot blot and polymerase chain reaction-restriction fragment length polymorphism analysis in 34 patients with idiopathic progressive sensorineural hearing loss (PSHL) and in 214 controls. The frequencies of DRB1*0301, DRB3*0101, DQB1*0201, and DPB1*0401 were significantly increased in patients with idiopathic PSHL compared with controls. The DQB1*0301 allele was significantly decreased in the patients. A linkage disequilibrium was probably responsible for the concomitant increase of both DRB1*0301 and DRB3*0101 alleles in patients. The increase of DQB1*0201 in patients was associated with the DRB1*0301 allele. In addition, the telomeric DPB1*0401 allele may act as an independent risk factor. The DQB1*0301 allele may have a protective role in the pathogenesis of idiopathic PSHL. These results suggest that the specific HLA class II gene products may confer susceptibility or resistance to idiopathic PSHL.

Adult↗
PubMed1996

[Glycerol electrocochleographic test: role of endolymphatic sac?].

The administration of a dehydrating agent like glycerol may improve the audiometric thresholds and decrease the summating potential in the electrocochleographic recordings of some Méière's diseases. There are many discussions concerning the endolymphatic sac's rôle in this cases. To clarify this subject we have reviewed the labyrinth's liquids physiopathology, the structural observations in cases of Ménière's diseases, the animals models date. We conclude that the presence of an endolymphatic sac is not necessary for obtaining a positive glycerol test. The clinical meaning of this test is discussed.

Audiometry, Evoked Response↗
PubMed1995

Detection of inner ear disease autoantibodies by immunoblotting.

To define further the character of autoantibodies against the inner ear in patients with inner ear disease, Autoantibodies in sera from 82 patients with inner ear disease were investigated by immunoblotting. The inner ear antigens were extracted from Hartley guinea pigs. Brain, kidney, lung, heart and liver extracts were also prepared. Antibodies against the inner ear were found in 32 of 82 (39%) patients with inner ear disease. These sera reacted with the 30 and 58 kDa bands of the inner ear extracts. The 30 kDa band was detected in sera from patients with various inner ear diseases, while the 58 kDa band reacted with sera of patients with idiopathic progressive sensorineural hearing loss. Only two of the 52 normal control sera had a very faint band at 30 kDa. Sixteen of 32 positive sera were then used to probe Western blots of the brain, kidney, lung heart and liver extracts. The 58 kDa band was also found in the protein extracts of the brain, the lung, and the liver. On the other hand, preliminary purification of the 30 and 58 kDa proteins from the inner ear extracts were achieved by anion exchange chromatography. These results show that antibodies in sera from patients with inner ear disease reacted with at least two polypeptide bands (30 and 58 kDa) of guinea pig inner ear extracts, and the 58 kDa antigenic epitope was not cochlea specific.

Adolescent↗
PubMed1995

The localization and specificity of guinea pig inner ear antigenic epitopes.

In this study, we investigated the relative localization of some antigenic epitopes in the inner ear. The inner ear protein antigens were extracted from various parts of the guinea pig inner ear. Brain, kidney, lung, heart and liver extracts were also obtained. We found by SDS-polyacrylamide gel electrophoresis that total inner ear extracts separated into three high concentration polypeptide bands with molecular weights of approximately 30, 42, 58 kd and three low density bands of 20, 25 and 35 kd. The 30 kd band was found mainly in the extract of the spiral ganglion and the acoustic nerve in the modiolus. The 42 and 58 kd bands were detected in the extract of the spiral ligament and the stria vascularis. The Organ of Corti and the basilar membrane extract gave rise to three bands of 30, 42 and 58 kd. Twenty-eight of the 75 sera from patients with inner ear disease reacted with the 30 and 58 kd bands of the inner ear protein extracts by immunoblotting. Sixteen of these 28 positive sera were then used to probe immunoblots of the brain, kidney, lung, heart and liver extracts. The 58 kd band was also found in protein extracts of the brain, the lung and the liver. This study suggests that the 30 kd antigenic epitope may be mainly related to the acoustic nerve and that the 58 kd antigenic epitope is not cochlear specific.

Animals↗
PubMed1995

[Guillain-Barré syndrome and hypacusia].

Guillain-Barré's Syndrome and hearing loss. A child presenting Guillain-Barré's syndrome, together with bilateral hearing loss is presented. The incidence of hypoacusis is unknown. The necessity of behavioural audiometry and electrophysiologic testing is stressed.

Audiometry, Pure-Tone↗
PubMed1993

High metabolic activity demonstrated by positron emission tomography in human auditory cortex in case of deafness of early onset.

Glucose metabolism has been studied in the auditory cortex of human subjects with deafness of early onset, and compared to normal subjects with ears plugged. The metabolism in the auditory cortex and in the association auditory cortex was higher in deaf subjects than in normal subjects. This result is compared to similar observations that we made previously in the visual cortex of human subjects with blindness of early onset.

Adolescent↗
PubMed1992

[Acute vertigo caused by cerebellar vascular accident].

At the beginning, small cerebellar strokes may present only with acute onset of vertigo, unsteadiness and unidirectional nystagmus, like a vestibular neuritis. In some cases, it is associated with tinnitus and hearing disturbance, like an endolymphatic hydrops. Other cases may mimic a benign cupulolithiasis, with only a paroxysmal positioning vertigo. Attention should be focused on transient associated symptoms: headache and blurred vision. One should not wait for classical cerebellar clinical signs: they are subtle and they appear late. Within a few days, the clinical picture will change: vertigo will disappear, while unsteadiness will progress. The electronystagmography confirms the integrity of the vestibular peripheric system. The cerebral CT Scan will show the ischaemic lesions only several days after the onset of the symptoms. A magnetic resonance imaging is far more efficient. Small cerebellar strokes have a good prognosis: complete recovery may be hoped with acetylsalicylic acid treatment and kinesitherapy.

Acute Disease↗
PubMed1992

[Etiology of deafness in children].

A retrospective etiological study of 112 files of deaf children is presented. A prenatal etiology is found in 42.8%, a perinatal in 19.6% and a postnatal in 13.4% of the cases. No cause was suspected in 30.3% of the cases. These results emphasise existing literature.

Chromosome Aberrations↗
PubMed1991

[Implantable hearing aids].

The purpose of these hearing aids is to improve the quantity and quality of amplification of the sound wave. Their operating principle is based on the existence of a transducer which transforms the electric signal captured by the microphone into a mechanical, vibrating wave. This transducer can act either directly on the temporal bone by short-circuiting the middle ear (and is then called a bone conduction implant) or directly on the ossicular chain (in which case it is called an ossicular transduction implant). A) There are 2 types of bone conduction implant: the "Audiant Bone Conduction" system of Hough-Vernon (Xomed), where an outside electromagnetic coil sends signals transcutaneously to a magnetic screw embedded on the temporal bone. Bone conduction must be normal. The "Bone Anchored Hearing Aid" (Nobelpharma) where the outside electromagnetic coil sends signals directly to the magnetic screw that is percutaneous. The mean thresholds in bone conduction can reach up to 45 dB. The drawbacks of this system lie in its inaesthetic appearance and the risk of infection. B) With ossicular transduction implants, the transducer may be: either an electromagnetic coil influencing a magnet fixed to the tympanum, on the ossicular chain, or replacing an element of the ossicular chain (these hearing aids are marketed by Richards); or a piezo-electric crystal which produces vibrations when it is subjected to an AC current, and which can be positioned on the stapes (Yanagihara). This system consumes less energy, gives excellent results for the high frequencies, but is more cumbersome.

Bone Conduction↗
PubMed1991

[Limits of the study of early auditory brainstem responses in the diagnoses of childhood deafness].

The author presents the results of his experience concerning brain stem evoked response in children. 122 cases are put forth. It shows that although behavioral audiometry is impossible in 7% of the cases, the BERA (Brain stem Evoked Response Audiology) is not reliable in 26.5% of the treble frequencies and 36% of the bass frequencies. Thus, it is not possible to equip children with hearing aids based on this given alone.

Adolescent↗