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Biomedical subjects

L Gilain

Publications and source records attributed to L Gilain.

At least 37 records · Page 2Linked to original sources
PubMed2001

Origin of cubic difference tones generated by high-intensity stimuli: effect of ischemia and auditory fatigue on the gerbil cochlea.

Cubic difference tone (CDT) otoacoustic emissions are thought to arise from the feedback loop allowing outer hair cells to enhance the sensitivity and tuning of the organ of Corti. The existence of residual CDTs during complete cochlear ischemia is therefore disturbing. That stimulus intensities must exceed 50-60 dB SPL for residual CDTs to be recorded and for level notches to be present in CDT growth functions is often cited as evidence for a two-component, "active/passive" model: one component, the residual one, would originate from a passive, hardly vulnerable mechanism and thus be unsuitable for hearing screening purposes. This model was probed in gerbil ears after complete interruption of the cochlear blood flow. Cochlear potentials and CDTs were controlled simultaneously through continuous monitoring of CDT level and phase for 50 and 60 dB SPL stimuli and group-delay measurements. After a clear initial decay, CDT levels elicited at 60 dB SPL plateaued for several minutes at about 20 dB below initial level, and when early level notches were observed, CDT phase changes remained minor. The CDT group delays decreased by less than 30%. Later CDT level notches were associated with sharp phase reversals but the similarity between CDT characteristics before and after a notch was hardly consistent with a two-component interpretation. When mild sound overexposure (pure tone, 90-95 dB SPL, 15-30 min) had been performed prior to ischemia, little or no ischemic CDT came from the frequency bands where auditory fatigue had been detected (within 1 kHz), irrespective of the stimulus intensity. It suggests that instead of being passive, residual ischemic CDTs were vulnerable and produced according to a near-normal tonotopy by the same mechanisms that were sensitive to auditory fatigue. All the results lined up with a simple feedback model of cochlear function assuming a single CDT source related to mechano-electrical transduction in outer hair cells. More parsimonious than a two-component model, it posits that although early stages of ischemia dramatically impair the overall performance of the cochlea, the nonlinear mechanical stages responsible for the existence of CDTs keep working albeit at higher intensities.

Acoustic Stimulation↗
PubMed2000

A prospective investigation of dispositional optimism as a predictor of health-related quality of life in head and neck cancer patients.

The aim of this study was to investigate the role of dispositional optimism (DO) as a predictor of health-related quality of life (HRQL) in a sample of upper aerodigestive tract cancer (UADT) patients. A prospective observational study design was used with a cohort of patients from one centre. DO was evaluated using a French version of the Life Orientation Test (the FLOT) translated and validated for this study. HRQL was evaluated using the EORTC QLQ-C30 prior to and 3 months following treatment. The association between FLOT ratings and HRQL was evaluated using linear multiple regression analysis and a two-way ANOVA with repeated measures. Baseline data were gathered on 101 subjects and follow-up data on 88 of these. The sample was dichotomized around the median FLOT score creating 'optimist' and 'pessimist' groups. Before treatment, optimists reported better role, cognitive and emotional function, less pain and fatigue and a better global rating of HRQL than did pessimists. Following treatment, optimists reported better role and cognitive functioning, less pain and better global HRQL than did pessimists. Pessimists reported a greater deterioration in the role domain following treatment than did optimists. At no point did pessimists rate HRQL better than optimists. The results suggest that optimism is associated with better HRQL in French UADT cancer patients.

Analysis of Variance↗
PubMed2000

Ventilator-associated sinusitis: microbiological results of sinus aspirates in patients on antibiotics.

BACKGROUND: The efficacy of systemic antibiotics on the treatment of ventilator-associated infectious maxillary sinusitis (VAIMS) is debated. The objective of this study was to determine the etiologic diagnosis of VAIMS in patients receiving antibiotics. METHODS: Patients mechanically ventilated for more than or equal to 72 h, who had persistent fever while on antibiotics for more than or equal to 48 h, underwent computed tomography scan followed by transnasal puncture of involved maxillary sinuses. VAIMS was defined as follows: fever greater than or equal to 38 degrees C, radiographic signs (air fluid level or opacification of maxillary sinuses on computed tomography scan), and a quantitative culture of sinus aspirate yielding more than or equal to 103 colony-forming units/ml. RESULTS: Twenty-four patients had radiographic signs of sinusitis. The mean +/- SD prior durations of mechanical ventilation and antibiotic exposure were 9.5 +/- 4.7 days and 6 +/- 4 days, respectively. Six unilateral and nine bilateral VAIMS were diagnosed in 15 patients. The median number of etiologic organisms per patient was two (range, one to four). The bacteriologic cultures yielded gram-positive bacteria (n = 21), gram-negative bacteria (n = 22), and yeasts (n = 5). Forty percent of causative agents were susceptible to the antibiotics prescribed. Seven patients with VAIMS developed 10 concomitant infections: ventilator-associated pneumonia (n = 5), urinary tract infection (n = 3), catheter infections (n = 2). In all cases of ventilator-associated pneumonia, the implicated agents were the causative agents of VAIMS. CONCLUSION: In VAIMS patients on antibiotics, quantitative cultures of sinus aspirates may contribute to establish the diagnosis. The frequent recovery of microorganisms susceptible to the antimicrobial treatment administered suggests that therapy of VAIMS with systemic antibiotics may not be sufficient.

Aged↗
PubMed2000

[Nasal soluble levels of ICAM-1 in allergic rhinitis].

UNLABELLED: Adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1), play an important role in the development of the inflammatory allergic response in the nose. ICAM-1 expression on nasal epithelial cells during allergic reaction is regarded as a major hallmark of allergic inflammation. OBJECTIVE: The aim of the study was to evaluate the levels of soluble ICAM-1 (sICAM-1) in nasal epithelial lining fluid (ELF) in patients with allergic rhinitis. PATIENTS: Seventeen patients with perennial allergic rhinitis (age: 34,6 +/- 14,6) were screened and the results were compared with those from 11 seasonal allergic rhinitis patients (age: 25.9 +/- 7.4) and 10 non-allergic patients. METHODS: The study was performed outside the pollen season. The scores of subjective symptoms were estimated by two differents methods. First, on the basis of a visual analog scale for the symptoms including nasal obstruction, rhinorrhea, sneezing and pruritus. This score was called "Autoscore" (fullmark =40 points). Second, on the basis of a four mark scale for each symptom defined (0 =no symptom, 1 =mild, 2 =moderate, 3 =severe). This score was called "Heteroscore" (fullmark =12 points). Specimens of nasal mucosa were collected by brushing the surface of nasal cavity. Levels of sICAM-1 and sECP (soluble Eosinophilic cationic protein) were measured by specific enzyme-linked immunosorbent assay. RESULTS: The levels of sICAM-1 in ELF were significantly higher (p <0.01) in patients with perennial rhinitis compared to patients with seasonal rhinitis outside the pollen season and to non allergic patients. Levels of sICAM-1 in patients with perennial allergic rhinitis were correlated with levels of sECP (p <0.003) and with the four mark scale scores (p <0. 03) but did not correlate with the visual analog scale scores. CONCLUSIONS: sICAM-1 increased in nasal secretions during natural perennial rhinitis and could be considered as a representative hallmark for clinical severity and follow-up evaluation in perennial allergic rhinitis.

Adult↗
PubMed2000

[Is there a correlation between optimism and quality of life in upper aerodigestive tract cancer Patients? Preliminary results].

UNLABELLED: The aim of this study was to test the hypothesis that optimism is a predictor of quality of life (QOL) in a sample of upper aerodigestive tract (UADT) cancer patients. MATERIALS AND METHODS: Consenting patients with squamous cell carcinoma of the UADT were included during the week following disclosure of the diagnosis of their illness, and before the start of treatment. QOL and optimism were evaluated by questionnaires presented to the patients before the start of treatment, after the treatment, and 6 and 12 months after the end of the treatment. PRELIMINARY RESULTS: 92 patients were included. The average age was 58.7+/-11.4 years. Their QOL scores were significantly correlated, first with age (r =- 0.23, p =0.03) and second with degree of optimism (r =0.32, p =0.002). No correlation was found between QOL scores, degree of optimism, and sociodemographic and clinical data. Optimism was the sole variable significantly associated with QOL before treatment (F =4.1, p =0.002, r(2) =0.19). The difference between QOL scores before and after treatment was not significant. CONCLUSION: Continuation of the study and analysis of survival of the patients may help pinpoint new prognostic factors, both objective and subjective, that will facilitate an overall approach to patient care by allowing for their preferences.

Adult↗
PubMed1999

[Features of tomodensitometry in the development of pleuropulmonary lesions related to Wegener's granulomatosis].

PURPOSE: The aim of this study was to determine CT scan value for the follow-up of patients with pleuropulmonary lesions related to Wegener's granulomatosis. METHODS: Retrospective study of ten patients who were diagnosed with diffuse Wegener's granulomatosis including lung involvement and for whom mean follow-up was 23 months (range 4-61). RESULTS: During early stages of the disease, the most common finding was the existence of either nodules (90% of the patients) or consolidations (100% of the patients). CT scan controls showed that nodules disappeared within 6 months in 60% of patients and had completely resolved after 12 months. Linear opacities relating to traction developed, replacing subpleural nodules. A pneumothorax occurred in two patients who had excavated subpleural nodules. Consolidations disappeared in 44% of the patients, most frequently within 4 months. When consolidations persisted, they were replaced by alveolar infiltrates accompanied by bronchiolectasies and linear opacities. Regarding either nodules or consolidations, CT features related to relapse were similar to those of initial lesions in 40% of the cases. CONCLUSION: The main features of pleuropulmonary lesions relating to Wegener's granulomatosis were subpleural nodules that either disappeared with, however, subsequent linear opacities sequelae, or were complicated by the occurrence of pneumothorax.

Adult↗
PubMed1999

Vulnerability of the gerbil cochlea to sound exposure during reversible ischemia.

Cochlear ischemia induces a sensorineural hearing loss, in part through a fast functional impairment of outer hair cellls. Assuming that the cochlea is rendered fragile during ischemia and reperfusion and that stimulation itself can jeopardize its functional recovery, we used a model of reversible selective cochlear ischemia in Mongolian gerbils to establish what type of sound exposure can be deleterious during and immediately after reversible ischemia. Several groups of gerbils were used, with different ischemia durations and levels of sound exposure. Control groups were only exposed to tones at 80 and 90 dB SPL during 30 min, while other groups underwent complete and fully reversible blockage of the labyrinthine artery, during 5.5 or 8 min, and were exposed to 60 or 80 dB SPL tones during 30 min. The amount of ischemia and reperfusion was measured by means of laser Doppler velocimetry, whereas outer hair cells' function was continuously monitored through distortion-product otoacoustic emissions (DPOAEs). The losses of DPOAE levels after 8 min transient ischemia and 60 dB SPL exposure were as large as those induced by 80 dB SPL exposures combined with 5.5 min ischemia, or 90 dB SPL exposures without ischemia, with a maximum loss around 25-30 dB, half an octave above the stimulus frequency. These results give evidence for an extremely high cochlear vulnerability to low-level sound exposure when associated with reversible ischemia. This vulnerability may have important clinical consequences in patients with cochlear circulatory disturbances.

Animals↗
PubMed1999

A model of cochlear function assessment during reversible ischemia in the Mongolian gerbil.

An in vivo model in the Mongolian gerbil is used to assess the auditory changes during reversible cochlear ischemia. This model allows the recordings of cochlear potentials (microphonics, summating potential and compound action potential) and otoacoustic emissions (cubic difference tones, CDTs), together with laser Doppler cochlear blood flow (CBF) measurements, over reversible cochlear ischemia. Ischemia is achieved by compression of the eighth nerve complex at the porus of the internal acoustical meatus, whereas the compression release allows the reperfusion to occur. While CBF monitoring permits to objectively determine the degree of ischemia and reperfusion, the combined analysis of cochlear potentials and CDTs makes it possible to point out the preferential site of main functional damage within the cochlea, i.e., outer hair cells (OHCs), inner hair cells, or ganglia cells. At least three ischemia-reperfusion sequences can be used on one side, and sometimes both ears can serve for experiments. This model could be applicable for testing drugs with alleged protective effects against cochlear ischemia and/or reperfusion, in treated vs. non-treated animals.

Animals↗
PubMed1999

[Postoperative pain assessment in head and neck cancer surgery: benefit of patient controlled analgesia (PCA)].

Acute postoperative pain has seldom been assessed in head and neck cancer surgery. The estimation of actual pain is more difficult when communication is impaired by tracheotomy or tracheostomia. The aim of the present prospective study was the assessment of analgesia level during the first 48 postoperative hours after head and neck cancer surgery. The analgesic procedure involved intra-venous morphine injected by means of a PCA pump (Patient controlled analgesia). Thirty patients were thus treated after cancer surgery of the larynx or the oropharynx. The protocol included during 48 hours the assessment of pain, using a visual analogic scale (VAS) every fourth hour, while recording the total injected dose of morphine, the localisation of pains, as well as the occurrence of side-effects. The control of postoperative pain was shown to be satisfactory, with a VAS grade smaller than 3 at time zero and kept below this value during 48 hours. At the end of this period, the mean total dose of morphine injected was 38 mg. No case of respiratory depression was even seen. It can be concluded that PCA seems to be an efficient procedure for controlling postoperative pain in head and neck cancer surgery. This technique proved to be better than delivering analgesia on requirement.

Acute Disease↗
PubMed1998

Assessment of postoperative pain after laryngeal surgery for cancer.

OBJECTIVES: To assess the intensity of postoperative pain after laryngeal surgery for cancer and the efficacy of analgesic injections at fixed hours. DESIGN: A prospective clinical study performed during the 3 days following laryngeal cancer surgery. SETTING: A university medical center. PATIENTS: Fifteen men (age range, 38-74 years) having just undergone a partial or total laryngectomy for epidermoid carcinoma. INTERVENTIONS: The analgesic treatment consisted of intravenous administrations at fixed hours (propacetamol or nalbuphine hydrochloride), with the possibility of rescue doses on demand. Pain and anxiety were assessed by means of visual analog scales (graduated from 0-10) every 3 hours on postoperative day 1, then every 6 hours on postoperative days 2 and 3. Objective criteria, ie, heart and respiratory rates and mean blood pressure, were measured with the same schedule. MAIN OUTCOME MEASURES: Postoperative pain and anxiety intensities and their variations were analyzed. Correlations between postoperative pain and other criteria were researched. RESULTS: Postoperative pain had a high initial level (maximum median, 7), then decreased and reached a score of 3 at the 30th hour. Unpredictable individual peaks of pain were reported. Anxiety was never high (maximum median, 4). No individual correlation was found between pain and objective parameters. CONCLUSIONS: After laryngeal surgery for cancer, pain can reach high levels, particularly in the first hours following recovery. Analgesic administrations at fixed hours are not effective enough. Postoperative analgesic treatment should aim to prevent the high initial pain and be individually adapted.

Acetaminophen↗
PubMed1998

CD1 hearing-impaired mice. I: Distortion product otoacoustic emission levels, cochlear function and morphology.

The levels of distortion product otoacoustic emissions (DPOAEs) were measured in a strain of hearing-impaired mutant mice (CD1) at various stages of outer hair cell impairment and compared to those of a control inbred strain (CBA/J). Parallel measurements of cochlear potentials and auditory brainstem evoked responses (ABRs) were performed and surface preparations of organs of Corti were observed using phalloidin staining of filamentous actin. Comparison of DPOAEs (elicited by stimulus levels of 60 and 70 dB SPL) with standard functional tests allowed the categorization of CD1 ears into two groups on the basis of the presence or absence of DPOAE, which corresponded to mean ABR thresholds greater or less than 40 dB nHL respectively. When adopting ABR threshold as the gold standard, this procedure yielded rates of false-positives and -negatives ranging from 5 to 16%. However, individual predictions of electrophysiological function from DPOAE levels were not accurate, owing to their large variance, and attempts to optimize stimulus levels did not reduce this variance. In contrast, the profiles of DPOAE level vs. f2 exhibited large correlations with ABR threshold profiles as a function of f2. It was also noteworthy that the mean levels of DPOAEs in CD1 mice recorded in frequency intervals with normal ABR thresholds were significantly smaller than those of CBA/J mice. Although hearing loss was revealed early both by DPOAEs and by other functional tests, surface preparations often remained normal until about 3-4 months of age.

Acoustic Stimulation↗
PubMed1998

Epithelial cell proliferation, apoptosis, and apoptosis inhibition in inverted papillomas.

Inverted papillomas (IPs) are rare benign tumors of nasal epithelium with high recurrence rates and malignant transformation potential. Their etiology is still uncertain, and the mechanism of their growth has not yet been fully described. The purpose of this study was to detect, quantify, and compare cell proliferation, apoptosis, and apoptosis inhibition in hyperplastic epithelium from IPs and in inflammatory nasal polyps (NPs). IP samples were obtained after surgical removal of tumor in 13 patients, and NPs were sampled during endoscopic ethmoidectomy in 10 patients with nasal polyposis. Cell proliferation and apoptosis inhibition, respectively, were assessed by immunohistochemical identification of the proliferating cell nuclear antigen (PCNA) and the oncoprotein Bcl-2. Apoptosis was evaluated by analyzing the DNA fragmentation. Cell proliferation and apoptosis were significantly higher in IPs than in NPs (P = .0002 and P = .043, respectively), while apoptosis inhibition was significantly lower in IPs than in NPs (P = .001). Concerning IPs, cell proliferation was significantly higher than apoptosis (P = .0029) and apoptosis inhibition (P = .0015). The increase in epithelial cell proliferation seemed to be greater in IPs with dysplasia than in IPs without dysplasia. Increased epithelial cell proliferation, but not apoptosis and apoptosis inhibition, seems to be involved in the development of IP.

Adult↗
PubMed1998

[Parapharyngeal tumors. Apropos of 6 cases].

We conducted a retrospective study of six patients presenting a parapharyngeal tumor and an analysis of data of the literature and recall classification of these tumors and their anatomo-clinics characters, therapeutic and diagnostic problems highlighting. These tumors are rare and have various origins, their treatment is almost always surgical by cervical approach which can be undertaken only after a rigorous exploration, systematically associating computed tomography scan and magnetic resonance imaging. Transoral resection is strongly advised against as it is potentially harmful.

Adenoma, Pleomorphic↗
PubMed1997

Monitoring of functional changes after transient ischemia in gerbil cochlea.

Ischemia and reperfusion are involved in numerous sensorineural pathologies. A model of reversible cochlear ischemia has been designed in Mongolian gerbil. Selective labyrinthine ischemia of variable duration (4-10 min) was achieved through a posterior transcranial approach. Ischemia and reperfusion were controlled with the help of laser Doppler velocimetry. Functional changes were monitored every 1-10 s throughout experiments, using cochlear potentials and otoacoustic emissions. After interruption of blood flow, all signals rapidly began to decay. In contrast to cochlear potentials, otoacoustic emissions always exhibited a plateau before reaching noise floor only after approximately 4-5 min. Upon ischemia release, cochlear blood flow recovered instantly and completely and cochlear potentials rapidly improved in most cases, in contrast to otoacoustic emissions that underwent a delayed decay after immediate partial recovery. The phase and group latency of otoacoustic emissions exhibited only small changes throughout ischemia and reperfusion, suggesting adaptive rather than damaging mechanisms. Cochlear function returned to normal after 5 min 30 s ischemia but longer complete ischemia sometimes led to irreversible damage despite the systematic presence of some recovery just after ischemia release. This behavior suggests that reperfusion in itself can be deleterious to a sensorineural organ and this model can be useful for identifying the noxious mechanisms of ischemia and reperfusion.

Animals↗
PubMed1997

Nasal cavity geometry measured by acoustic rhinometry and computed tomography.

OBJECTIVE: To determine the significance of cross-sectional areas obtained by acoustic rhinometry. DESIGN: Comparison of data obtained by acoustic rhinometry and computed tomography (CT). SETTING: Outpatient clinic. PATIENTS: Nine adults with nasal obstruction due to turbinate hypertrophy. MAIN OUTCOME MEASURES: Acoustic rhinometry and CT were performed after nasal decongestion. The acoustic area-distance curve was analyzed based on 3 notches (A1, A2, and A3) corresponding to 3 local minimal areas. Computed tomographic measurements were made in the coronal plane at 0.5-cm intervals, and the narrowest sections in the anterior (S1), middle (S2), and posterior (S3) parts of the nasal cavity were selected. Mean specific section areas and volumes were computed by integration of the acoustic area-distance curves using the same procedure for the 2 methods. RESULTS: Significant correlations were found between acoustic and CT areas in the anterior nasal cavity (A1 vs S1, P < .001; A2 vs S2, P < .005). Acoustic and CT anterior volumes from A1 to A2 and from S1 to S2 were significantly correlated with each other (P < .005). No correlation was found between acoustic and CT areas measured at the posterior part of the nose (A3 vs S3). A weak correlation was evidenced between acoustic and CT posterior volumes from A2 to A3 and from S2 to S3 (P < .05). CONCLUSIONS: Acoustic rhinometry may be particularly well suited to the evaluation of anterior nasal geometry during clinical studies. At the posterior part of the nose, acoustic measurements may be of limited clinical relevance.

Acoustics↗
PubMed1997

Cellulitis due to Streptococcus pneumoniae with diminished susceptibility to penicillin in an immunocompromised patient.

A 74-year-old man with multiple myeloma developed facial and cervical cellulitis and severe sepsis as a complication of surgery (alar region basal cell carcinoma). The etiological agent was, surprisingly, penicillin-resistant Streptococcus pneumoniae (PRSP). The patient successfully received 16 days of antibiotics. Amoxicillin was given as monotherapy during the last 14 days of treatment. PRSP can be responsible not only for otitis media, pneumonia or meningitis, but also for various other types of infection in patients with predisposing factors.

Aged↗