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Biomedical subjects

C Dubreuil

Publications and source records attributed to C Dubreuil.

At least 55 records · Page 3Linked to original sources
PubMed1997

Myogenic vestibular-evoked potentials in normal subjects: a comparison between responses obtained from sternomastoid and trapezius muscles.

Brief intense clicks cause short latency microcontraction of cervical muscles. Several studies have supported the hypothesis that these microcontractions are of vestibular origin. Averaging these muscular responses enables us to obtain myogenic vestibular evoked potential (MVEP). The receptor of these responses is thought to be the saccule, afferent pathways being the vestibular nerve and efferent pathways the vestibulospinal tract. However, discrepancies are reported with regard to results obtained in healthy subjects: some authors obtained symmetrical response to monaural clicks whereas others obtained responses of greater amplitude on the muscle ispilateral to stimulation. These discrepancies may be due to the presence of different recording sites (inion, sternomastoid or trapezius muscles). The aim of this study was to clarify MVEP results in healthy subjects, using a simple non-traumatic method, and to compare the results obtained on sternomastoid (SM) and trapezius muscles (TRP). Sixteen normal hearing healthy subjects were involved. Latencies and amplitude of both SM and TRP muscle were reproducible in the same subject. Patterns of response were similar to those obtained in previous studies. Following binaural and monaural stimulations, latencies of MVEP were symmetrical on both muscles and amplitudes tended to be greater on muscles contralateral to stimulation, which conflicts with previous results in the literature. Whatever the type of stimulation, latencies of responses obtained on SM were significantly shorter (mean = -3.8 ms), and amplitudes lower (mean = -7.1 microV), than those obtained on TRP. Binaural stimulation resulted in responses of greater amplitude compared to monaural (mean = 0.45 microV). Given the intrasubject reproducibility of the responses, these methods allow MEVP to be recorded in a standardized and reproducible way.

Adult↗
PubMed1996

Transient evoked otoacoustic emissions in nonsurgical ear.

Several studies have reported contralateral hearing deficits following ear surgery. This study aimed to evaluate changes in micromechanical cochlear properties which could occur in the contralateral ear following ear surgery, using transient evoked otoacoustic emission (TEOAE) recording. Surgery involved tympanic membrane surgery in 13 cases and middle ear surgery in 16 cases. TEOAEs were recorded and compared for contralateral ears before (day 1: D1) and after (day 2: D2) ear surgery. Two patients failed to show a TEOAE reproductibility > 75%, and were excluded from the study, thus reducing the number of patients to 27. Results were compared to those of a control group of 12 normal hearing subjects, recorded in similar conditions also on day one (D1) and day two (D2). The difference between D1 and D2 was not significant in either group. Pre/postsurgery variations in TEOAE amplitude for the patient group were negatively and significantly correlated with the corresponding preoperative levels in that the greater the presurgical TEOAE level, the larger the decrease in postoperative level. Compared to the variation confidence intervals in the control group, TEOAE amplitude remained stable in 15 patients, increased in four and decreased in eight. These three groups of patients differed only regarding preoperative TEOAE amplitude values, which were significantly greater in the group which presented a decrease in TEOAE amplitude than in the others. Increase in TEOAE amplitude was more frequent after tympanic membrane surgery. On the other hand, TEOAE amplitude decrease was more frequent after middle ear surgery, and is significant compared to the tympanic membrane surgery results. The results show that cochlear micromechanical properties may be reduced in the ear contralateral to surgery and that this decrease depends on the severity of the surgical procedures in the operated ear, such as drilling or opening of the oval window.

Acoustic Stimulation↗
PubMed1996

Clinical interest of brainstem auditory evoked potentials in 72 children with inadequate language development.

The present study is of brainstem auditory evoked potentials (BAEP) in 72 children, of 2 to 13 years of age, showing inadequate language development. The age of the children was mainly below the age of 4 (39 cases = 54%), peaking between 3 and 4 years of age (33 cases = 46%). Even so, 82% of our patients were 3 years old or over: 64% were boys, 36% girls, the proportion of boys falling off with age 26% (19 cases) of BAEPs recorded were normal, 74% (53 cases) pathological. High prevalence of undiagnosed hearing loss was found. Physiopathological BAEP classification showed endocochlear impairment in 68% (36 cases), conductive impairment in 21% (11 cases) and retrocochlear impairment in 11% (6 cases) of subjects. Unilateral impairment (20 cases = 28%) cannot account for inadequate language development; but, in the 8 cases (11%) of total bilateral hearing loss, and the 15 cases (21%) of partial bilateral impairment, hearing loss more or equal to 50 dB HL, impaired hearing would play a role in the retardation.

Aging↗
PubMed1995

Acute otitis media in children: a study of nasopharyngeal carriage of potential pathogens and therapeutic efficacy of cefixime and amoxicillin-clavulanate.

We conducted a large, multicenter, randomized, open-label study throughout France comparing the efficacy and safety of cefixime suspension (8 mg/kg/day, b.i.d., for 10 days) versus amoxicillin-clavulanate suspension (80 mg/kg/day, t.i.d., for 10 days) in 510 children (ages 6 to 36 months) with acute otitis media. The most frequent microorganisms colonizing the nasopharynx at the start of treatment were Streptococcus pneumoniae (51.5%), Haemophilus influenzae (45%) and Moraxella catarrhalis (30.2%). Rates of beta-lactamase positivity were 32.1% and 95.3% for H. influenzae and M. catarrhalis, respectively. Decreased susceptibility of S. pneumoniae to penicillin was found in 39.7% of isolates. Clinical efficacy was 87.8% (223/254) for cefixime and 87.0% (215/247) for amoxicillin-clavulanate. At the 5-week follow-up visit, relapse had occurred in 15.7% (31/197) of cefixime-treated patients and in 15.6% (32/205) of those treated with amoxicillin-clavulanate. We conclude that these two regimens are equally effective in acute otitis media in children.

Acute Disease↗
PubMed1995

[Sonomotor vestibular reflex in acoustic neuroma].

Despite recent advance in diagnosis and surgical techniques of acoustic neuroma, ideal criteria for hearing preservation attempt remain unsatisfactory. This study reports sonomotor vestibular reflex recorded pre and postoperatively in 20 patients with acoustic neuroma. Hearing preservation was attempted according to tumor size and preoperative pure tone audiometry results. The studied population was divided in 2 groups according to hearing preservation was attempted (group 1 n = 13, retrosigmoid approach) or not (group 2 n = 7, translabyrinthin approach). In accordance with postsurgical audition, the subjects of group 1 were distributed in group 1-A (postsurgical preserved audition n = 4) or group 1-B (postsurgical unpreserved audition n = 9). Presurgical sonomotor vestibular reflex in response to pathological stimulation were compared in the different groups. In preoperative period, sonomotor vertibular reflex in response to pathological side stimulation were present in all the patients of group 1-A with a similar amplitude to those obtained when stimulating healthy side. In 6 subjects of group 1-B these responses were present but with a smaller amplitude than those obtained when stimulating healthy side. The responses were absent in 3 subjects of group 1-B and in all the subjects of the group 2. These result tend to demonstrate that preoperative presence of sonomotor vestibular reflex in response to neuroma side stimulation with amplitude similar to those obtained by healthy side stimulation is a favorable criterion for hearing preservation attempt. On the opposite, the decrease in the amplitude of these responses or their absence seems to be unfavorable for hearing preservation attempt.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Effects of buflomedil and naftidrofuryl on the human cochlear microcirculation measured by laser-Doppler].

The aim of this study was to assess the effects on cochlear blood flow measured by laser-Doppler of two vasoactive agents known for their supposed effectiveness in the presbyacousy treatment (buflomedil, naftidrofuryl), 16 patients undergoing acoustic neurinoma surgery were studied. Cochlear blood flow (CBF) was continuously recorded after the head of the probe was inserted into the internal ear through the round window. Systolic arterial pressure (SAP) and heart rate (HR) were continuously recorded via an arterial cannula. Hemodynamic variations due to buflomedil (400 mg in bolus) and to naftidrofuryl (200 mg in bolus) were compared with those of sodium nitroprusside (500 micrograms in bolus) in each case with anova. Buflomedil did not alter CBF (0%), SAP (+0.14 +/- 1.7%), HR (+3.4 +/- 3.4%). Naftidrofuryl provoked a significant decrease (P < 0.05) of CBF (-14.5 +/- 7.55%), SAP (-13.7 +/- 4%), and a significant increase (P < 0.05) of HR (+8.5 +/- 3.5%); there is a relationship between CBF and SAP (r = 0.88 P < 0.05). NPS provoked a significant decrease (P < 0.01) of CBF (-34.7 +/- 7.7%) SAP (-26.8 +/- 5.4%) and a significant increase (P < 0.01) of HR(+14.7 +/- 7.3%) in the same way of naftidrofuryl (P < 0.01). In conclusion, human cochlear microcirculation depends upon pharmacological hemodynamic variations such as animal models or middle ear microcirculation. If buflomedil did not alter it, naftidrofuryl provoked a reduction by a direct vasodilator effect inducing hypotension like sodium nitroprusside.

Cochlea↗
PubMed1994

Effects of posture, hypotension and locally applied vasoconstriction on the middle ear microcirculation in anaesthetized humans.

Studies by laser-Doppler flowmetry of middle ear microcirculation changes induced by physical and chemical stimuli in the animal have only recently been made. This prospective study, performed in humans, was designed to compare the effects of a postural manoeuvre (headup tilt 30 degrees), hypotension and locally applied vasoconstriction on middle ear blood flow during anaesthesia. Circulatory changes provoked by a headup tilt of 30 degrees, and successive intravenous boluses of potent vasodilators, were compared with circulatory changes provoked by locally applied adrenaline, in ten healthy patients in good physical states undergoing middle ear surgical repair. Heart rate and direct arterial pressure were continuously recorded via a radial artery cannula. Middle ear blood flow was continuously recorded via a laser-Doppler probe placed on the promontorium cavi tympani. Metabolic parameters (partial pressure of O2 and CO2 in arterial blood, pH, arterial lactate concentrations) and arterial concentrations of propofol were measured just before and just after the experiment. Headup tilt did not modify heart rate, mean arterial pressure or middle ear blood flow. Vasodilators (nicardipine, nitroprusside, nitroglycerin) provoked a fall in arterial pressure (P < 0.0001, P < 0.0001, P < 0.019, respectively), but did not induce any significant variations in heart rate; variations occurred in middle ear blood flow (P > 0.05, not significant) which were different according to patients and agents. Locally applied adrenaline provoked a fall in the middle ear blood flow (P < 0.0012), with no effect on heart rate and arterial pressure. There were no significant changes in metabolic values, or propofol serum concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Otosclerosis: stapedectomy or stapedotomy. A long-term comparative study. Apropos of 1279 cases].

The authors report 1279 surgical operations of otosclerosis performed between 1980 and 1992 in 959 operated patients. They chose the autegenous vein or perichondrium interposition TeflonR piston; however this technique has improved over the past few years. The size of the stapedectomy has been diminishing; from total, then partial stapedectomy, at last to 0.8 mm across stapedotomy. The graft has become exclusively from venous origin and the diameter of the piston has been reduced from 0.8 to 0.6 then to 0.4 mm. Seven groups of patients have been examined according to the size of the incision for stapedotomy or stapedectomy and the size of the piston. The audiometric study was realized after one month, one year, three years, fine or even ten years after surgery. Comparative tests were made considering the sex and the age of the patient, the thinness of the graft, and surgical revisions. The audiometric study lied not only upon the audiometric Rinne's closing but also upon the bone conduction variation (postoperative bc-preoperative bc) in the course of time. The evolution of tinnitus, of vertigo has been, as well, the subject of a careful study in time according to the surgical techniques. The study shows that the audiometric results (Rinne's closing, bc evolution) are statically much better with total stapedectomy, then with partial stapedectomy, at last with stapedotomy in the first three postoperative years. The best audiometric results are obtained with wider pistons (0.8 mm diameter) and venous approach. The results regarding tinnitus and vertigos are dissimilar especially during the first operative year. After three years of evolution, the significant audiometric differences tend to reduce and the audiometric results become the same (no significant difference) whatever the surgical technique may be. After three years, simple, calibrated stapedotomy without interposition statically gives similar results in literature. However, each surgical technique may, though rather infrequently, produce some incidents or complications that undoubtedly influence the operator as for the choice of the surgical technique to use.

Audiometry↗
PubMed1992

Neoadjuvant combination of carboplatin and 5-FU in head and neck cancer: a randomized study.

A prospective, randomized, multicenter study of patients with oropharyngeal and pharyngolaryngeal tumors compared locoregional treatment alone with neoadjuvant chemotherapy with carboplatin/5-fluorouracil (5-FU) followed by locoregional treatment. The aim of the study was to evaluate the role of chemotherapy on survival and on the need for mutilating surgery. Since 1988, 219 patients (105 with oropharyngeal and 114 with pharyngolaryngeal tumors) have entered the study. All patients randomized to neoadjuvant chemotherapy received three cycles of carboplatin 400 mg/m2 day 1 and 5-FU 1 g/m2/d as a continuous infusion days 1 through 5 every 3 weeks. Neoadjuvant chemotherapy was given to 108 patients. The 268 evaluable courses induced a low rate of grade 3 or 4 toxicity. Four patients (3.6%) died of major complications. The complete response (CR) rate was 31%, which represented a decrease in mutilating surgery of 30%. (Patients with CRs had radiotherapy alone instead of radiosurgical treatment as originally planned.) The objective response rate was 61%. Survival curves for the chemotherapy and chemotherapy-naive groups were not significantly different. The rate of nodal recurrence was significantly higher in the chemotherapy group, however, and chemotherapy did not decrease the rate of second primary tumors or distant metastases. Thus, the justification for neoadjuvant chemotherapy may be a decreased rate of mutilating surgery. These preliminary results are encouraging, but follow-up is as yet too short to allow definite conclusions.

Adult↗
PubMed1992

Effects of celiprolol, a cardioselective beta-blocker, on respiratory function in asthmatic patients.

The aim of this study was to compare the pulmonary effects of a single dose of celiprolol 400 mg, versus bisoprolol 20 mg and the combination of celiprolol 400 mg plus propranolol 40 mg versus placebo plus propranolol 40 mg. We conducted a double-blind randomized cross-over study in 10 stable asthmatic patients (mean age +/- SD 31 +/- 7 yrs) with forced expiratory volume in one second (FEV1): 2.5 +/- 0.7 l. A three-day washout period preceded each treatment period. Measurements of respiratory function were done before treatment and after 90, 120 and 180 min. There was a significant increase of FEV1 (+12%) and forced vital capacity (FVC) (+8%) after celiprolol (p less than 0.05) and a decrease of FEV1 (-9%) after propranolol. Concerning the combination, celiprolol inhibits the bronchoconstrictor effects of propranolol. We conclude that celiprolol has bronchosparing properties in asthmatic patients, and even improves some of the ventilatory parameters.

Adrenergic beta-Antagonists↗
PubMed1991

Betahistine dihydrochloride versus flunarizine. A double-blind study on recurrent vertigo with or without cochlear syndrome typical of Menière's disease.

This study was designed to compare the efficacy and safety of betahistine dihydrochloride and flunarizine. All patients included in this multicenter, double-blind, randomized trial showed a specific pattern of vertigo, i.e. recurrent paroxysmal vertigo with or without the cochlear symptoms typical of Meniere's disease. Fifty-five patients were treated for 2 months (28 in the betahistine group and 27 in the flunarizine group). Analysis of intra-group symptom changes demonstrated a greater efficacy for betahistine. Statistically significant decreases in duration and severity of attacks, and in the presence of vegetative symptoms were seen in the betahistine group after the first and second months of treatment, whereas in the flunarizine group this was the case only at the end of the first month of treatment. Furthermore in the betahistine group, statistically significant decreases occurred for the other major criteria, including number of attacks, evidence of vestibular dysfunction, and presence of cochlear symptoms. Adverse effects were similar to those reported in previous studies of both products: stomach pains only with betahistine, and drowsiness, asthenia, and depression with flunarizine.

Betahistine↗
PubMed1991

[Value of oto-endoscopy in the follow-up treatment of cholesteatoma of the middle ear].

The endoscopic approach to the middle ear in eradication of cholesteatoma is now very frequently realised as in the control of the cavities of the middle ear in second stage of cholesteatomas for revision. The improvement of eradication will help to prevent recurrent cholesteatoma and to manage ossiculoplasty. Retraction pockets must also lead to endoscopic control and management.

Cholesteatoma↗
PubMed1991

Microflora of the nasopharynx in Caucasian and Maghrebian subjects with and without nasopharyngeal carcinoma.

The possible role of bacteria in the etiology of nasopharyngeal carcinoma (NPC) was studied by bacteriological and biochemical analyses of nasopharyngeal swabs collected in the cavum and in the fossa of Rosenmüller of NPC patients and healthy controls in France and Algeria. Counts of total bacteria and of total nitrate-reducing bacteria, mainly enterobacteria, were higher in the Maghrebians than in the Caucasians. The composition of the bacterial flora was different: in Maghrebians, enterobacteria were present in five of 17 control subjects and eight of 15 NPC patients, while the prevalence was only one out of 15 control subjects in Caucasians. Twelve of 32 bacterial species isolated from Caucasians and Maghrebians with normal or tumorous nasopharyngeal microflora were able to catalyse nitrosation of morpholine in vitro. This result suggests that colonization of the nasopharynx by microflora that contain nitrate-reducing microorganisms which can form N-nitroso compounds might represent a risk factor for NPC in Maghrebian populations.

Algeria↗