Search PubMed⌕ Search

Biomedical subjects

V Couloigner

Publications and source records attributed to V Couloigner.

15 recordsLinked to original sources
PubMed2002

[Na transport in the cochlea of mammals].

Endolymph, the fluid that bathes the apical side of the inner ear sensory cells, is a K-rich and Na-poor fluid. In the cochlea, various epithelial transport systems involved in the transport of Na from the apical endolymphatic to the basolateral perilymphatic compartments have been identified: basolateral Na+, K(+)-ATPase, apical non selective cationic channels, Na+/H+ exchanger, and ENaC epithelial Na channel. These transporters may be involved in physiological and pathological processes in which endolymph Na concentration is high.

Animals↗
PubMed2001

H+,K+-ATPase is not involved in endolymph pH homeostasis.

In endolymph, the calculated electrochemical gradients suggest the presence of active transport of H+ and K+. The presence of H+,K+-ATPase, an active transporter that mediates the exchange of intracellular H+ for extracellular K+, was investigated using reverse transcription-polymerase chain reaction on rat microdissected inner ear tissues. Distal colon and kidney were used as positive controls. The two H+,K+-ATPase colonic or gastric isoforms were not detected in the rat cochlea and endolymphatic sac. This result suggests that H+,K+-ATPase is not involved in H+ and K+ endolymph homeostasis.

Acid-Base Equilibrium↗
PubMed2001

Location and function of the epithelial Na channel in the cochlea.

In the cochlea, endolymph is a K-rich and Na-poor fluid. The purpose of the present study was to check the presence and to assess the role of epithelial Na channel (ENaC) in this organ. alpha-, beta-, and gamma-ENaC subunit mRNA, and proteins were detected in rat cochlea by RT-PCR and Western blot. alpha-ENaC subunit mRNA was localized by in situ hybridization in both epithelial (stria vascularis, spiral prominence, spiral limbus) and nonepithelial structures (spiral ligament, spiral ganglion). The alpha-ENaC-positive tissues were also positive for beta-subunit mRNA (except spiral ganglion) or for gamma-subunit mRNA (spiral limbus, spiral ligament, and spiral ganglion), but the signals of beta- and gamma-subunits were weaker than those observed for alpha-subunit. In vivo, the endocochlear potential was recorded in guinea pigs under normoxic and hypoxic conditions after endolymphatic perfusion of ENaC inhibitors (amiloride, benzamil) dissolved either in K-rich or Na-rich solutions. ENaC inhibitors altered the endocochlear potential when Na-rich but not when K-rich solutions were perfused. In conclusion, ENaC subunits are expressed in epithelial and nonepithelial cochlear structures. One of its functions is probably to maintain the low concentration of Na in endolymph.

Action Potentials↗
PubMed2000

Effect of locally applied drugs on the pH of luminal fluid in the endolymphatic sac of guinea pig.

The aim of the present work was to assess the effect of various drugs applied locally on the pH of the luminal fluid (pH(lum)) in guinea pig endolymphatic sac. pH(lum) and transepithelial potential, when measured in vivo by means of double-barrelled pH-sensitive microelectrodes, were 7.06 +/- 0.08 and +6.1 +/- 0.34 mV (mean +/- SE; n = 84), respectively, which is consistent with a net acid secretion in the luminal fluid of the endolymphatic sac. Bafilomycin and acetazolamide increased and decreased, respectively, pH(lum). Amiloride, ethylisopropylamiloride, ouabain, and Schering 28080 had no effect on pH(lum). Results obtained with inhibitors of anionic transport systems were inconclusive; e.g., DIDS reduced pH(lum), whereas neither SITS nor triflocin had any effect. We conclude that bafilomycin-sensitive H(+)-ATPase activity accounts for the transepithelial acid gradient measured in the endolymphatic sac and that intracellular and membrane-bound carbonic anhydrase probably participates in regulating endolymphatic sac pH(lum). The relationship between acid pH, endolymph volume, and Ménière's disease remains to be further investigated.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1999

[Autoimmune deafness].

UNLABELLED: A REAL ENTITY: Deafness resulting from an autoimmune mechanism is suggested by a growing number of clinical and experimental arguments. The audio-vestibular system is known to be involved in a certain number of systemic diseases, particularly Cogan's disease. In other cases, the inner ear alone is involved; deafness may be the first manifestation of a systemic disease or result from a possible immunological mechanism. CLINICAL ASPECTS: Autoimmune deafness is very invalidating. Bilateral perception deafness is observed in 80% of the cases and vestibular involvement is found in 70% DIAGNOSIS: No one simple reliable test is known which can establish the diagnosis of autoimmune deafness. Other causes must be ruled out by appropriate clinical and complementary explorations. For humoral immunity, the western blot method has given promising results suggesting a possible role of the heat shock protein in the underlying immunological mechanism. TREATMENT: Immediate care is needed but no standard treatment has been defined. High-dose corticosteroids can provide symptom relief, particularly in case of abnormal immunological tests. The role of immunosuppressive therapy, sometimes proposed in case of corticosteroid resistance, remains to be defined.

Adrenal Cortex Hormones↗
PubMed1999

Surgical treatment of the high jugular bulb in patients with Ménière's disease and pulsatile tinnitus.

The aim of this retrospective study was to evaluate the functional results of surgical lowering of the high jugular bulb in the treatment of patients with Ménière's disease and pulsatile tinnitus. Fifteen patients with disabling Ménière's disease associated with pulsatile tinnitus and a high and medial jugular bulb were included in this study. As treatment a complete mastoidectomy was performed, after which the jugular bulb was freed by an infralabyrinthine and subfacial approach. The bulb was then displaced downwards with surgical wax. Functional results of surgery were assessed by a questionnaire according to the 1995 guidelines of the United States American Academy Committee on Hearing and Equilibrium, audiometric and vestibular tests, and by magnetic resonance and computed tomographic imaging with vascular sequences. Surgical treatment was contraindicated in two cases: one had hypoplasia of the contralateral sigmoid sinus and the other a small petrous hemangioma located around the jugular bulb that was discovered peroperatively. Among the 13 patients treated by definitive surgery, attacks of vertigo were reported as disabling in 12 cases preoperatively (92%) versus 1 (8%) after surgical treatment. No significant change in hearing was observed after surgery. Tinnitus had been reported in all patients preoperatively and decreased in intensity in four (31%) and disappeared in three (23%) after surgery.

Adult↗
PubMed1999

Evidence for apical K conductance and Na-K-2Cl cotransport in the endolymphatic sac of guinea pig.

The transepithelial potential in the endolymphatic sac (ESP) was recorded up to 60 min after apical injection of ouabain, bumetanide, quinine, barium, tetraethylammonium, and 4-aminopyridine. After control injection, ESP decreased by 74% and completely recovered at 30 min. After ouabain, barium, or quinine injection, the ESP time course was similar to that in the control group. After bumetanide, tetraethylammonium, or 4-aminopyridine injection, complete recovery was only observed at 60 min. These results suggest that apical K+ conductance and Na-K-2Cl cotransporter could be involved in the genesis of ESP.

Animals↗
PubMed1999

In vivo study of the electrochemical composition of luminal fluid in the guinea pig endolymphatic sac.

The aim of this study was to investigate the ionic composition (sodium, potassium) of the luminal fluid in the endolymphatic sac and to correlate it with the transepithelial potential. Experiments were performed in guinea pigs using either an intradural posterior fossa approach or a translabyrinthine approach. The endolymphatic sac transepithelial potential (ESP) was measured and the luminal fluid was sampled. The sodium, potassium and protein concentrations were determined. The results were: i) the luminal fluid in the endolymphatic sac differs in composition from perilymph, on the one hand, and from both cochlear and vestibular endolymph, on the other hand, indicating that the endolymphatic sac maintains chemical (sodium, potassium) and electrical (ESP) gradients; ii) the calculated osmolarity (Na + K) x 2 was about 230 mosm/l; iii) no correlation was observed between sodium and potassium concentrations; iv) large interindividual variations exist from one animal to another, suggesting physiological variations in the functional status of the endolymphatic sac. In conclusion, the variation in composition of the endolymphatic sac luminal fluid reflected variations in ion transport by the epithelium and thus a possible adaptation of the ion transport to different physiopathological conditions.

Animals↗
PubMed1998

Effect of locally applied drugs on the endolymphatic sac potential.

In Ménière's disease, an inner ear disorder related to an endolymphatic hydrops, an alteration of the functioning of the endolymphatic sac has been proposed. The endolymphatic sac is assumed to be involved in the secretion/resorption of endolymph. The epithelial transport systems have been indirectly studied by the recording of the endolymphatic sac transepithelial potential (ESP) in control conditions and after the local injection of drugs such as diuretics that have been proposed in the treatment of Ménière's disease. The ESP was recorded, in vivo, in guinea pigs up to 150 minutes after the perisaccular injection of 5 microL of a 150 mmol/L (mM) NaCl solution containing various drugs known to inhibit ionic transport systems. The initial ESP was +8.4+/-0.3 mV (mean +/- SEM, n = 78). The basolateral injection of 5 microL of 150 mM NaCl induced an ESP decrease of 64%+/-6.0% (n = 12), 5 minutes after the end of the injection. Then ESP increased, returning to its initial value at 60 minutes and surpassing it at 120 minutes. Diuretics such as acetazolamide (10[-3] mol/L [M]), an inhibitor of carbonic anhydrase, and amiloride (10[-4] M), an inhibitor of Na channel or Na/H exchanger, decreased the ESP recovery. At variance, bumetanide (10[-6] M, 10[-4] M), the Na-K-Cl cotransport inhibitor, and chlorothiazide (10[-4] M), a Na-Cl cotransporter inhibitor, failed to alter the ESP as compared with the control group. Ouabain (10[-3] M), the Na+,K+-adenosine triphosphatase (ATPase) inhibitor, prevented the ESP recovery otherwise observed 60 minutes after the NaCl injection. Bafilomycin A1, the inhibitor of the vacuolar-type H+-ATPase, prevented the recovery of the ESP with a log-dose/effect (10[-5] M, 10[-6] M, 10[-8] M). Disulfonic acid stilbene (DIDS) (10[-4] M), an inhibitor of transporters involving HCO3-, also prevented the ESP recovery. These results suggest that the genesis of the ESP was highly dependent on acid-base transport systems including carbonic anhydrase, a vacuolar-type H+-ATPase, and an anionic transport system blocked by DIDS. Further studies are needed to confirm the alteration of the acid-base balance in this epithelium and its possible involvement in the pathogenesis of Ménière's disease.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1997

In situ lifetime, causes for replacement, and complications of the Provox voice prosthesis.

One hundred Provox voice prostheses consecutively inserted in 37 patients and replaced only when phonation was impaired or complications noted were analyzed for in situ lifetime, causes for replacement, and complications. The mean in situ lifetime was 311 days. Actuarial analysis (Kaplan-Meier method) of the in situ lifetime revealed that 65.9%, 23.7%, and 16.4% of the voice prosthesis were still in situ by the 6th, 12th, and 18th postinsertion month. Cause for replacement was salivary leakage through the prosthesis valve, salivary leakage around the prosthesis, deterioration of the prosthesis, and excessive crusting resulting in increased airflow resistance in 33%, 27%, 24%, and 16% of cases, respectively. Complications included granulation tissue formation, cervical cellulitis, necrosis of the tracheoesophageal puncture, tracheostomal stenosis, and swallowing impairment in six, two, one, three, and one patient, respectively.

Actuarial Analysis↗
PubMed1996

[Venous hemangioma of the temporal muscle. Review of the literature: apropos of a case].

A 41-year-old woman progressively developed a painful tumefaction in the left temporal fossa. The scan showed a isodense intramuscular structure weakly enhanced by contrast medium. Surgical exeresis was performed via the coronal access. Histology of the surgical specimen reported the diagnosis of venous muscular haemangioma. The diagnosis and management of these rare tumours is discussed.

Adult↗
PubMed1996

[Supra-cricoid partial laryngectomy extended to the anterior arch of the cricoid with tracheo-crico-hyoido-epiglottopexy. Oncologic and functional results].

21 patients with glottic carcinoma presenting anterior infraglottic extent of tumor, classified T2-T4, were offered and extended supracricoid partial laryngectomy with tracheocricohyoidoepiglottopexy (TCHEP) between 1979 and 1994 at our department. The technique for the procedure, the duration of tracheotomy tube, naso-gastric feeding tube, and hospital stay are presented. Postoperative complications and management were described. The 5-year actuarial survival, local control, nodal recurrence, distant metastasis, and metachroneous second primary tumor estimate was 74.7%, 88.9%, 11.1%, 22.4% and 15%, respectively. Overall a 95.2% (20/21) local control rate was achieved with a 90.5% (19/21) laryngeal preservation rate.

Actuarial Analysis↗
PubMed1993

[Pleomorphic adenoma of the nasal septum. Apropos of a case].

Pleomorphic adenoma is the common benign tumor of glandular tissue occurring in the head neck region. The authors report a case localised in the nasal septum, which is an uncommon site for this tumor. Symptoms include unilateral nasal obstruction and intermittent nasal bleeding. Local surgical resection with histologic clear margins is the treatment of choice but long term follow-up is recommended.

Adenoma, Pleomorphic↗
PubMedDate not supplied

Inner ear pressure in Menière's disease and fluctuating hearing loss determined by tympanic membrane displacement analysis.

Menière's disease and fluctuating hearing loss are related to labyrinthine fluid pressure variations. The development of a new indirect method of analysis of the tympanic membrane displacement during the stapedial reflex, using the Marchbanks Measurements System (MMS 10), allows us to study inner ear fluid pressure during these pathological conditions. In this study, measurements with this method were made in four groups of patients: a control group with normal hearing (n=7), stable sensorineural hearing loss (n=9), fluctuating hearing loss (n=8), and Menière's disease (n=25). Results show, first, a good relationship between the recording of negative curves, suggesting a high pressure, and the acute episodes of fluctuating hearing loss; and, secondly, in the case of Menière's disease two types of situation: positive and negative curves suggesting normal and high pressures, respectively.

Adult↗