Biomedical subjects

P Tran Ba Huy

Publications and source records attributed to P Tran Ba Huy.

At least 19 recordsLinked to original sources

PubMed2005

Postural control in patients with unilateral vestibular lesions is more impaired in the roll than in the pitch plane: a static and dynamic posturography study.

The postural instability of patients with vestibular loss (11 with bilateral and 101 with unilateral vestibular loss) at different times following the lesion was investigated by means of posturography and compared to healthy subjects. In addition, subjects submitted to galvanic vestibular stimulation were also studied to compare their postural performances with those of patients with complete unilateral vestibular lesion. The platform consisted of a static computerized force platform, on which a seesaw platform could be placed to test the subjects in dynamic conditions. The displacement of the center of foot pressure was measured under different conditions: subjects standing on the fixed platform, eyes open and eyes closed and subjects standing on the seesaw platform, eyes open and eyes closed. In the last condition, balance was tested in the subject's pitch plane by allowing the platform to rotate forwards and backwards only and in the patient's roll plane by allowing the platform to rotate to the left and to the right. The results showed that in static conditions, only bilateral vestibular loss patients had abnormal values compared to controls. In contrast, in dynamic eyes-closed conditions, both bilateral and unilateral patients could be differentiated from controls. Bilateral patients were unable to stand up without falling in both pitch and roll planes. Unilateral patients fell in the first week following the lesion and exhibited increased postural oscillations in both planes from the 2-week up to the 1-year postlesion stage. In addition and more importantly, they fell more often or had higher sway in the roll than in the pitch plane. Therefore, this study suggests that dynamic posturography on a seesaw platform could be a valuable tool for clinical diagnosis and quantitative analysis of imbalance in patients suffering from a unilateral vestibular loss up to 1 year after the lesion.

Accidental Falls↗

PubMed2005

[Idiopathic sudden sensorineural hearing loss: a review].

Idiopathic Sudden Sensorineural Hearing Loss (ISSHL) remains one of the major unsolved otologic emergencies. It is characterized by the onset of an unilateral sensorineural hearing loss developing within 24 hours, and averaging on pure tone audiogram at least 30 dB HL for three subsequent octave steps, with no marked vestibular symptoms and no identifiable cause. ISSHL is a syndrome covering several heterogeneous entities resulting from different pathogenetic mechanisms. At this time, the audiogram is the unique tool which may help clinicians to identify these entities and provide a classification based on 5 types of hearing loss. Numerous experimental and clinical studies have investigated the mechanisms by which infectious, ischemic, mechanic or immunologic insults may induce cochlear dysfunction. However, extrapolation to humans and rationale therapeutic approaches to ISSHL remain uncertain. SSHL being a diagnosis of exclusion, retrocochlear and neurologic etiologies should be eliminated. No argument allows to consider ISSHL a therapeutic emergency. More precisely, the experimental data presently available on cochlear physiology suggests that a treatment could have some chance to be effective if undertaken within minutes following the onset of ISSHL, a condition never encountered in daily practice. Conversely, it is not justifiable to impute the absence of hearing recovery to a delay in therapy. The various therapeutic strategies currently recommended are highly empirical and should be questionned in terms of cost-effectiveness, the most common being high-dose corticosteroids. New investigation tests are required for improving our approach to ISSHL.

Diagnosis, Differential↗

PubMed2005

Enhanced sodium absorption in middle ear epithelial cells cultured at air-liquid interface.

CONCLUSION: As we demonstrated previously that transcription of alpha-ENaC was correlated with oxygen tension in the culture medium, this study suggests that the increase in alpha-ENaC expression observed under ALI conditions may result from greater oxygenation of ME cells. OBJECTIVE: The physiology of the middle ear (ME) is primarily concerned with keeping the cavities fluid-free, to allow transmission of sound vibrations from the eardrum to the inner ear. ME epithelial cells are thought to play a key role in this process as they actively absorb sodium and water in order to clear any excess fluid present in the cavities. MATERIAL AND METHODS: As an air-liquid interface (ALI) model has been shown to improve differentiation and enhance sodium absorption in other respiratory epithelia, we established an ALI model for ME cells. RESULTS: ME cells cultured under ALI conditions exhibited a fourfold increase in sodium absorption, which was not related to either a metabolic effect or to enhanced morphological differentiation, but instead to an increase in expression of the alpha-subunit of the epithelial sodium channel (alpha-ENaC).

Absorption↗

PubMed2005

["Endolymphatic" cochleo-vestibular disorders].

Certain peripheral vertigos undoubtedly do not raise from neuro-sensorial structures but rather of the secretory structures and can be called "endolymphatic". They deserve to be individualized because concerning different pathogenic mechanisms and certainly are relevant for a specific treatment. We hope that in the next years new investigation tools will allow to explore in a noninvasive way the endolymphatic contents and dysfunctions of these structures.

Endolymph↗

PubMed2004

Reliance on visual information after stroke. Part I: Balance on dynamic posturography.

OBJECTIVE: To test the hypothesis that postural imbalance after stroke may be caused by inability to use pertinent somatosensory, vestibular, or visual information. DESIGN: Description of the sensory organization of patients with hemiplegia. SETTING: Public rehabilitation center in France. PARTICIPANTS: Forty patients with hemiplegia after a single hemisphere stroke who were at least 12 months post stroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The patients performed computerized dynamic posturography (EquiTest), which is designed to assess a patient's ability use sensory inputs separately and to effectively suppress inaccurate inputs in case of sensory conflict. Body stability under each of 6 sensory conditions was assessed by an equilibrium score (ES). RESULTS: In conditions of altered somatosensory information, with visual deprivation (ES5) or visuovestibular conflict (ES6), the median scores for patients with hemiplegia (ES5-43; ES6-20) were significantly lower than those for normal subjects (ES5-69; ES6-67). CONCLUSIONS: Many patients with hemiplegia seem to rely on visual input. The mechanism of this excessive visual reliance is discussed. Rehabilitation programs of postural control for the patients with hemiplegia should take into account the possible impairment of sensory organization and should include exercises to be performed under conditions of sensory input deprivation and sensory conflict.

Cerebral Cortex↗

PubMed2004

Vertebrobasilar occlusive disorders presenting as sudden sensorineural hearing loss.

BACKGROUND: Isolated sudden sensorineural hearing loss (SSHL) has been rarely related to vertebrobasilar occlusive disorders (VBOD). This is an important issue for both neurologists and otolaryngologists, since the management and prognosis of this type of hearing loss widely differs from that of hearing loss from other causes. OBJECTIVES: To describe the clinical characteristics and report the incidence of SSHL related to VBOD. METHODS: Retrospective analysis of clinical charts from 333 patients admitted for SSHL in a large ear, nose, and throat emergency tertiary care center from 1999 to 2002. RESULTS: Four cases (1.2%) of VBOD as the unique cause of SSHL were diagnosed among 333 patients. The most typical features of these cases were the presence of one of the following characteristics: (1) bilateral SSHL, (2) associated occipital or posterior nuchal pain, and (3) the occurrence of delayed neurologic deficits. The underlying vascular disease affected the vertebral arteries: dissection in two cases and atherosclerosis in two other cases. The audiometric features of hearing loss were endocochlear in one case, of both types in one case, and unknown in two cases. Hearing recovered partially or completely. CONCLUSIONS: Our results confirm the low incidence of SSHL related to VBOD and show that the observation of endocochlear audiometric features cannot preclude a central cause in SSHL. The clinical presentation of our cases related to VBOD emphasize that a careful follow-up of any patient with SSHL is warranted and that the presence of nuchal pain suggestive of arterial dissection in younger subjects, a past history of atherosclerosis or embolism in older patients, or the occurrence of delayed associated neurologic symptoms should be considered with particular caution in this situation.

Adult↗

PubMed2003

[Endoscopic resection of the frontal sinus floor following the Draf procedure: long term results and therapeutic algorithm].

OBJECTIVES: Endoscopic resection of the frontal sinus floor is a minimally invasive and functional surgical procedure designed for the treatment of inflammatory sinus diseases, which avoids the side-effects of external osteoplastic obliteration. The aim of the study was to evaluate long term results and to determine computed tomographic criteria predictive of success. PATIENTS AND METHODS: Our study reports the results of 20 patients operated for nasofrontal stenosis associated or not with osteitis or secondary mucocele. RESULTS: A successful result was obtained in 90% with a mean follow-up of 3.5 years. Failures (2) were attributed to insufficient resection and to frontal sinus osteogenesis. CONCLUSION: Endoscopic frontal sinusotomy is a safe and effective procedure for large sinuses with large distance between nasion and cribriform plate, but not in case of osteogenesis and multiple mucoceles. In case of unfavourable anatomy, or for the aforementioned pathologies, the obliteration procedure should be preferred.

Adolescent↗

PubMed2003

[Vascular complications after acoustic neurinoma surgery].

OBJECTIVE: To report six cases of vascular complications occurring after acoustic neuroma surgery and to discuss the postoperative signs and symptoms that should alert the surgeon, in order to undertake the appropriate treatment as soon as possible. METHODS: Four hundred thirty-two cases of acoustic tumors operated by the same surgeons between January 1991 and December 2000 were reviewed. RESULTS: Six cases of vascular complications were identified: one case of cerebral vasospasm secondary to persistence of subarachnoid blood after injury to Dandy's vein; three cases of arterial infarction giving rise to a partial anterior inferior cerebellar artery (AICA) syndrome with an unusual nystagmus in two cases (ipsilateral in one patient and strong controlateral in one patient presenting preoperative vestibular areflexia); one case of hematoma of the cerebello-pontine angle (CPA) causing strong ipsilateral nystagmus; and one case of venous infarction of the cerebellar vermis secondary to accidental sinus thrombosis. CONCLUSIONS: Vascular complications after acoustic neuroma surgery are potentially devastating and should be identified as early as possible. Rapid extubation is recommended for systematic neurologic assessment. Among abnormal signs and symptoms that should alert the surgeon, marked nystagmus ipsilateral to the operated side or contralateral in patient presenting preoperative vestibular areflexia appears to be of great value.

Adult↗

PubMed2003

[Exploration of olfactory difficulties].

Sense-of-smell disorders are a frequent occurrence at ORL clinics. The clinical exploration must include a thorough and comprehensive interview to discover the etiology. The clinical examination is easily performed using cold-light endoscopes, which can reveal anatomical or mucous membrane pathologies, even in far- situated anatomical parts. The access to olfactometric examinations is limited by the small number of health centers which have the proper equipment and trained staff. Guided by the initial interview and clinical exploration, the diagnosis of smell disorder can benefit from the conclusive and factual contribution of the CAT scan and MRI.

Diagnostic Imaging↗

PubMed2002

Intratympanic gentamicin injections for Meniere disease: vestibular hair cell impairment and regeneration.

The authors treated 22 patients with intratympanic gentamicin. Vestibular function was measured using caloric and head impulse tests and vestibular evoked myogenic potentials induced by high amplitude sounds and short duration galvanic currents. Roughly one-third of the patients, after initially losing their caloric responses and displaying refixation saccades to head impulse tests, recovered within 2 years of the lesion. Vertigo did not recur in patients in whom the galvanic response was abolished.

Adult↗

PubMed2002

[Is sudden sensorineural hearing loss a therapeutic emergency? Early results in a prospective cohort of 136 patients].

Idiopathic sudden sensorineural hearing loss is one of the most controversial issues in otology. A prospective cohort study including 136 sudden hearing losses seen at the ENT emergency referral center of Lariboisiere Hospital during an 18-month period was conducted. Patients were hospitalized and a corticotherapy course was administered, eventually associated with an antiviral treatment, low molecular weight dextran or sedative. At the end of the 5-day hospitalization, 74% of the patients had recovered, at least partially, with a mean gain of 22 dB. The outcome was considered satisfactory, i.e. superior to 50% of the initial loss, in 30% of the patients. After 1 month, 86% of the patients recovered at least partially with a mean gain of 30 dB. The outcome was considered satisfactory in 44% of the patients. A prognosis analysis showed that vertigo, age of the patient and anacusis are pejorative factors. Ascending audiogram shapes seem to involve a better prognosis. The therapeutic delay is not correlated with the quality of the outcome, which questions the classical notion of therapeutic emergency.

Adrenal Cortex Hormones↗

PubMed2002

[Contribution and Cost-Effectiveness of ABR and MRI in Acoustic Neuroma screening. Retrospective Study of 151 Cases].

The aim of this study was to retrospectively assess during two periods (1991-1995 and 1996-2000) if MRI spreading had changed: (1) private ENT physicians screening habits; (2) the average tumor size at the time of diagnosis and the diagnostic delay of acoustic neuroma; and (3) the cost of acoustic neuroma diagnosis. In addition, the sensibility of each diagnostic test was calculated on 151 tumors. Our results show no significant change neither in the screening strategy (except a mild decrease in CT-scan utilization) nor in the tumor size, diagnostic delay or diagnostic cost between the two periods. Even if MRI is the gold standard for acoustic neuroma diagnosis, our 86%-sensibility of ABR, increased to 99% if combined with stapedial reflex and caloric test may still incline to use ABR in selected cases.

Adolescent↗

PubMed2002

[Pediatric rhabdomyosarcoma of the infratemporal fossa].

OBJECTIVE: Prognosis of rhabdomyosarcoma of the infratemporal fossa is generally poor. We report our experience. MATERIAL AND METHODS: Twenty-three children with rhabdomyosarcoma of the infratemporal fossa were treated at the Gustave Roussy and Curie Institutes between 1984 and 1999. Seventeen children received radiotherapy (group 1), four children were treated surgically with or without postoperative radiotherapy (group 2), and two children received no further treatment after chemotherapy (group 3). RESULTS: In group 1, there were 10 local recurrences and one metastatic failure; all 11 children died from their disease. Nodal recurrence was salvaged successfully in one other with chemotherapy and surgery. In group 2, three children were disease free at 3 years and one died of local recurrence. In group 3, one child experienced a local recurrence successfully salvaged with radiotherapy. This child was disease free at 3 years. The other child developed local recurrence and died. DISCUSSION: Overall survival rate in our patients was 50%. Local control remained the main prognostic factor for survival. Surgery has already been shown to improve local control in other localizations of rhabdomyosarcoma. If residual tumor tissue remains after neo-adjuvant chemotherapy, surgery should be considered in a multidisciplinary discussion of therapeutic options. Indications for postoperative radiotherapy depend on age and histological features of the surgical specimen.

Adolescent↗

PubMed2002

[Scintigraphy by l'Octreoscan in the management of head and neck paragangliomas].

OBJECTIVE: To assess the usefulness of somatostatin receptor scintigraphy [Octreoscan] in a series of 18 patients referred for a suspicion of paraganglioma of the head and neck between July 2001 and February 2002. PATIENTS AND METHODS: Sixteen patients had one or several paragangliomas of the head and neck diagnosed on conclusive conventional imaging including CT and MR scan. In two patients, radiological data were not conclusive. Planar images were obtained 4 and 24 hr after the iv injection of 148-185 MBq [Octreoscan]. RESULTS: Twenty-two hot spot lesions were detected. Twenty of these lesions corresponded to the twenty known paragangliomas. The volume of the smallest tumor was 0.2 cm(3). In one patient, intense thyroid nodule uptake led to the surgical diagnosis of oncocytoma. In two lesions, where conventional imaging was not conclusive, arteriography showed a typical aspect of meningioma; one patient was operated on and histology confirmed this diagnosis. No evidence of abnormal uptake was seen in site previously operated on (3 patients). CONCLUSION: Octreotide scintigraphy is a very sensitive method for detection of paraganglioma of head and neck. It provides information on potential tumor sites in the whole body after one single injection. It could be used as a screening test in patients at risk (familial or known paraganglioma) in order to detect paraganglioma at an early stage and, thus to reduce the surgical morbidity, as well as in the follow-up after surgery to detect recurrences.

Adult↗

PubMed2002

[Hemangiomas and superficial vascular malformations of the face and neck].

Hemangiomas and superficial vascular anomalies of the head and neck form what usually calls the angiomas. Many terms exist in the literature for that reason the classification of the ISSVA, admitted by most of the doctors, helps us in naming the different anomalies. The processing of this pathology needs a multidisciplinary collaboration with doctors of different specialties. The evolution of the radiological, surgical techniques of laser, and who knows, of the research, allows to hope us to cure some of the particularly dangerous anomalies like the arteriovenous malformations. We presented here the different technics used in 2001 in the management of hemangioma and superficial vascular anomalies insisting on a multidisciplinary approach.

Adult↗

PubMed2001

Vestibular projections in the human cortex.

There is considerable evidence from studies on cats and monkeys that several cortical areas such as area 2v at the tip of the intraparietal sulcus, area 3av in the sulcus centralis, the parietoinsular vestibular cortex adjacent to the posterior insula (PIVC) and area 7 in the inferior parietal lobule are involved in the processing of vestibular information. Microelectrode recordings from these areas have shown that: (1) most of these cortical neurons are connected trisynaptically to the labyrinthine endorgans and (2) they receive converging vestibular, visual and somatosensory inputs. These data suggest that a multimodal cortical system is involved in postural and gaze control. In humans, recent positron emission tomography (PET) scans and functional magnetic resonance imaging (fMRI) studies have largely confirmed these data. However, because of the limited temporal resolution of these two methods, the minimum time of arrival of labyrinthine inputs from the vestibular hair cells to these cortical areas has not yet been determined. In this study, we used the evoked potential method to attempt to answer this question. Due to its excellent temporal resolution, this method is ideal for the investigation of the tri- or polysynaptic nature of the vestibulocortical pathways. Eleven volunteer patients, who underwent a vestibular neurectomy due to intractable Meniere's disease (MD) or acoustic neurinoma resection, were included in this experiment. Patients were anesthetized and the vestibular nerve was electrically stimulated. The evoked potentials were recorded by 30 subcutaneous active electrodes located on the scalp. The brain electrical source imaging (BESA) program (version 2.0, 1995) was used to calculate dipole sources. The latency period for the activation of five distinct cortical zones, including the prefrontal and/or the frontal lobe, the ipsilateral temporoparietal cortex, the anterior portion of the supplementary motor area (SMA) and the contralateral parietal cortex, was 6 ms. The short latency period recorded for each of these areas indicates that several trisynaptic pathways, passing through the vestibular nuclei and the thalamic neurons, link the primary vestibular afferents to the cortex. We suggest that all these areas, including the prefrontal area, process egomotion information and may be involved in planning motor synergies to counteract loss of equilibrium.

Brain Mapping↗

PubMed2001

Cochlear electrical stimulation: influence of age of implantation on Fos immunocytochemical reactions in inferior colliculi and dorsal cochlear nuclei of the rat.

The influence of age at the time of implantation of a stimulating electrode unilaterally in the inner ear on central auditory pathways was investigated in rats deafened shortly after birth. Immunoreactivity for Fos served as a functional marker of neuronal activity. Electrodes were implanted in the left cochlea of rats aged 3 weeks or 4 months. Stimulation lasted 45 minutes, then rats were sacrificed and tissues processed for immunocytochemistry. The younger animals showed significantly more neurons with Fos immunoreactivity bilaterally in the dorsal cochlear nuclei (DCN) and inferior colliculi (IC) than the older rats or control animals with normal hearing receiving the same stimulation. Activity was more prominent in the left DCN and right IC. The results show that electrical stimulation of the inner ear is more effective in younger animals in eliciting gene expression associated with development of a functional network in the auditory pathways. This suggests that deaf children should be provided with cochlear implants as early as possible.

Age Factors↗

PubMed2001

Serous or mucoid effusion in the course of secretory otitis media: influence of ion transport modulation.

OBJECTIVE: Secretory otitis media is defined by a chronic effusion in the middle ear cavities, behind an intact tympanic membrane without acute infection. In the course of secretory otitis media, the effusion is sometimes thick (or mucoid) and other times thin (or serous). For several authors, these differences might be related to different inflammatory levels rather than to distinct pathophysiological mechanisms. The purpose of this study was to determine whether the modulation of ion transport by inflammation could account for the differences observed in the aspect of ME effusion. METHODS: Hydrogen peroxide (H2O2), used as an inflammation model was tested on a middle ear cell line (MESV) in culture. RESULTS: Results show that low and high concentrations of H2O2 have opposite effects on ion (and then water) absorption by the middle ear epithelium. CONCLUSION: the modulation of ion and water absorption by inflammation could modify the mucins concentration in the effusion, and explain observed viscosity differences in the course of secretory otitis media.

Anti-Infective Agents, Local↗