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Biomedical subjects

O Michel

Publications and source records attributed to O Michel.

At least 19 recordsLinked to original sources
PubMed1992

Effects of prostaglandin E2 on the fluctuating hearing loss in Ménière's disease.

To elucidate the possible mediating role of prostaglandins as underlying mechanism of the acute audiologic effects of furosemide in patients with Ménière's disease, the hearing threshold shift after a 1 hour infusion of a commercially available prostaglandin E2 derivative (120 ng/kg body weight) was determined in 10 patients. Prostaglandin E2 produced a transient hearing improvement comparable to the effects obtained in the furosemide test with 1.2 mg/kg bw in the same patients. The effectiveness of a prostaglandin infusion on hearing levels may be a further sign of the involvement of this mediator in hearing processes.

Adult↗
PubMed1992

Relation between the bronchial obstructive response to inhaled lipopolysaccharide and bronchial responsiveness to histamine.

BACKGROUND: Bronchoconstriction has developed after inhalation of lipopolysaccharide in a dose of 20 micrograms in asthmatic patients and of 200 micrograms in normal subjects. This study set out to determine whether the bronchial response to lipopolysaccharide was related to non-specific bronchial responsiveness and atopy. METHODS: Sixteen subjects with a fall in specific airway conductance of 40% (PD40sGaw) after inhaling up to 900 micrograms histamine inhaled 20 micrograms lipopolysaccharide (from Escherichia coli type 026:B6) a week after bronchial challenge with a control solution of saline. The bronchial response over five hours was measured as change in FEV1 and area under the FEV1-time curve. RESULTS: FEV1 fell significantly more after lipopolysaccharide than after diluent inhalation, the difference in mean (SE) FEV1 being 4.6% (5.4%); response was maximal 60 minutes after lipopolysaccharide inhalation and lasted more than five hours. Histamine PD20FEV1 and PD40sGaw correlated with the fall in FEV1 after lipopolysaccharide inhalation. There was no difference in the proportions of responders and non-responders to lipopolysaccharide who were atopic. CONCLUSION: Lipopolysaccharide induced bronchial obstruction is associated with non-specific responsiveness but not with atopy.

Administration, Inhalation↗
PubMed1992

Inflammatory response to acute inhalation of endotoxin in asthmatic patients.

Inhalation of 20 micrograms endotoxins (from the membrane of Gram-negative bacteria) has been reported to induce a bronchial obstructive response in asthmatic subjects. The aim of the present study was to evaluate in asthmatic patients the possibility of an inflammatory response to inhaled endotoxins. Eight patients with mild asthma were submitted to bronchial challenge tests, in a single-blind trial, on Day 1 with control solution and on Day 7 with 20 micrograms endotoxin of Escherichia coli (026:B6). Local inflammatory response was indirectly evaluated by the degree of bronchial hyperresponsiveness (BHR) expressed as PD20 FEV1 histamine (the dose of histamine inducing a 20% decrease in FEV1) at 0, 6, 24, and 48 h and 7 days. Systemic inflammation was investigated by sequential blood determinations of total (and differential) white cells, complement anaphylatoxin C5a, interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and C-reactive protein (CRP). A significant (p < 0.01) bronchial obstructive response was demonstrable 45 min after lipopolysaccharide (LPS) inhalation, lasting 5 h. Comparing the level of BHR after control inhalation, a significant (p < 0.05) increase in BHR was shown 6 h after LPS, partially normalized at 24 and 48 h. A short peak in TNF-alpha at 60 min (p < 0.05) and an increase in total white blood cells (p < 0.01) and neutrophil polymorphonuclear neutrophils at 360 min (p < 0.05) and of CRP at 24 and 48 h (p < 0.05 and p < 0.01) were significant. The other blood parameters did not change significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1992

Hearing loss as a sequel of lumbar puncture.

Only a few case reports have been published about hearing impairment following lumbar puncture, and not all were thoroughly documented by audiograms. We present nine cases of hearing loss following myelography, lumbar puncture, and spinal anesthesia. We speculate that this rare complication arises only in persons with a wholly or partially patent cochlear aqueduct, and occurs via the release of perilymphatic fluid in the cerebrospinal space. Hearing loss was seen in eight of the nine patients in the lower frequencies, and in six of the nine patients on both sides. Recovery to normal hearing was noticed in six of the nine patients. Transient hearing loss may occur more often than it is generally assumed, and the symptom can remain unnoticed. Since not all of these hearing losses proved to be fully reversible, we suggest informing patients about this complication for medicolegal reasons.

Adult↗
PubMed1991

Probational treatment of sudden deafness with prostacyclin: a pilot study.

Sudden idiopathic hearing loss has occasionally been supposed to be caused by a disturbed microcirculation in the inner ear of unknown origin. Little is known about the regulation of cochlear blood flow and the effectiveness of drugs in cochlear microcirculation. Because animal experiments gave evidence that prostacyclin (PGI2) might be one biochemical substratum of local regulators in the flow of blood in the stria vascularis, 11 patients with sudden idiopathic hearing loss were treated once for 6 h with prostacyclin (10 ng/kg body weight/min) in a first open clinical trial. In most cases prostacyclin increased hearing level (mean value: 7.4 dB/frequency/day) more than a standard therapy with pentoxifylline. The substitution of PGI2 could be another indication of a rheologic disorder--whether per se or within a larger context of inflammation-like interaction--in the inner ear of patients with sudden hearing impairment.

Adult↗
PubMed1991

[Placebo-controlled double-blind study of the treatment of sudden hearing loss with a stable prostacyclin analog].

A placebo-controlled, double-blind study with the stable prostacyclin analog Taprosten (CG4203, Grünenthal, Aachen, FRG) on the treatment of sudden hearing loss was conducted in 22 patients in the ENT Department of the University of Cologne. The hospital ethical committee gave permission for the trial. After informed consent had been obtained, the patients (13 male, 9 female, age 21-74 yrs.) were treated with Taprosten (25 ng/kg bodyweight/minute intravenously) or with 30 ml saline solution (NaCl 0.9%) for 6 hours during 5 days. Hearing thresholds were controlled by pure tone audiometry and speech discrimination test each day before and after treatment. All the data obtained (dB hearing loss) by pure tone audiometry was averaged for 7 frequencies. Differences were calculated between the hearing loss before and after treatment. Differences were considered significant if p less than or equal to 0.01. No significant difference could be seen in hearing recovery after Taprosten and placebo during the 5 days of treatment. Evaluation of the individual frequencies showed no prevalence of higher or lower frequencies. Although the impression was that hearing loss recovered better within the first days of treatment with Taprosten, no statistical proof could be found. In both groups the percentage of complete recovery did not differ (about 70%). The reason for the lack of significant statistical differences was the high standard deviation of the averaged hearing loss and the very high spontaneous recovery. Even if, in this placebo-controlled study, we could not prove the efficacy of a prostaglandin treatment for sudden hearing loss, the need for multicentred placebo-controlled studies with more patients is evident.

Adult↗
PubMed1991

[Endoscopically-controlled endonasal orbital decompression in malignant exophthalmos].

In 6 patients with endocrine ophthalmopathy, indications, surgical technique and results of the endoscopic controlled endonasal orbital decompression are described in comparison to the common surgical procedures. When medical and radiation therapy fail, indications for decompression are a) loss of visual acuity or visual field defects, b) increasing strabismus, c) severe keratopathy due to eyelid retraction. The endoscopic-controlled endonasal surgical decompression technique is proceeded in three steps. First, an endonasal ethmoidectomy with resection of the middle turbinate is performed and the medial wall of the maxillary sinus is widely opened. Second, the medial and inferior wall of the orbital walls are removed, preserving the infraorbital nerve. In the last step, the periorbital area is incised and the orbital fat herniates. The advantages of this procedure consist in the absence of exterior scars and the known morbidity of a Caldwell-Luc antrotomy. The results were documented by computed tomographic scans (CT), magnetic resonance imaging (MRI), Hertel measurements, evaluation of ocular motility and ophthalmoscopy. An average of 3-4 mm improvement in Hertel-measurements could be reached. All patients had a postoperative improvement of visual acuity. 2 patients developed more significant diplopia postoperatively, whereas in all other patients ocular motility either improved or rested unaffected. Therefore, the endoscopic controlled endonasal procedure allows to obtain comparable results to the common extranasal and transantral procedures without the disadvantages of the latter.

Aged↗
PubMed1991

Domestic endotoxin exposure and clinical severity of asthma.

Endotoxins are potent pro-inflammatory substances present in several natural environments and in commercial house dust extracts. To investigate the possible effect of chronic endotoxin exposure on asthma, 28 patients with perennial chronic asthma (20 allergic to house dust mite and eight intrinsic asthmatics) were evaluated during a 4-month period (lung function, clinical and immunological criteria). At the same time, two house dust samples were collected from each patient's home to determine total house dust weight (mg/m2), endotoxin concentration and house dust mite antigen content (evaluated indirectly by guanine content with HPLC method). The mean (+/- s.d.) endotoxin concentration, as measured by quantitative Limulus assay was 2.59 (+/- 3.41) ng/mg house dust, ranging from 0.12 to 20 ng/mg. The mean guanine content was 0.13 (+/- 0.16) mg/100 mg house dust. There was no correlation between endotoxin and house dust mite concentrations. Patients were compared according to the low or high grade exposure to dust, endotoxins and guanine. Compared with patients with low grade (less than or equal to 5.6 ng/ml) exposure, subjects exposed to high endotoxin concentrations (greater than 5.6 ng/ml) showed a significant increase in dyspnea (median 2.6 vs 3.3; P less than 0.05) and treatment (median 14 vs 44.3; P less than 0.01) scores, oral corticosteroid (median 0.0 vs 13.5 mg/24 hr; P less than 0.01) and beta 2-mimetics (median four vs eight puffs/day; P less than 0.01) intake, and a significant decrease in FEV1/FVC (median 84.5 vs 67% of predicted value; P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effect of endotoxin contamination on the antigenic skin test response.

Bacterial lipopolysaccharides (LPS), the major part of endotoxin, are proinflammatory substances present in the natural environment. Lipopolysaccharides enhance allergen-induced histamine release from human basophils of allergic subjects. The aim of this study was to assess the LPS activity on the allergy skin test response. Twenty patients allergic to house dust mite (HDM) underwent skin prick tests with LPS (E coli 026: B6 serotype) at concentrations of 1, 10, 100 micrograms/mL, with HDM extracts at different dilutions, and with solutions of LPS mixed with HDM. Endotoxin alone did not induce any immediate skin response; LPS had a synergistic effect on the HDM skin response both in terms of flare [27.4 +/- 2.8 mm, 26.6 +/- 3.3 mm, 28.1 +/- 2.5 mm versus 20.7 +/- 3.6 mm, respectively in presence of LPS 1 (P less than .02), 10 (P less than .05), 100 (P less than .01) micrograms/mL] and wheal response [6.4 +/- 1.0 mm, in presence of LPS 100 micrograms/mL versus 4.9 +/- 1.1 mm in absence of LPS (P less than .05)]. On the other hand, a possible LPS synergistic action on the histamine skin response was evaluated in ten normal subjects but the results were not significant. These findings show that LPS increases the allergy skin response probably due to a mechanism including a potentiation of the IgE receptor activation rather than an increase of the skin response to the release mediators.

Adult↗
PubMed1991

[Postoperative inhalation treatment after paranasal sinus interventions. A placebo-controlled, double-blind and randomized study].

A placebo-controlled, double-blind study with Ems brine inhalations as postoperative treatment after endoscopic endonasal sinus surgery was conducted on 30 patients. After informed consent had been obtained, the patients were treated with either Ems brine or saline solution (200 ml) 3 times a day for 10 days. The parameters measured were rhinomanometry, X-ray films of the sinuses, endoscopy, saccharin clearance and a subjective evaluation by the physician and by the patient based on a visual analogue scale. The difficulty of choosing parameters for assessing the treatment was that comparable clinical studies and a single predictive parameter were not available. The bacteriological test and the saccharin clearance test were not significantly different between the two groups. Recovery, swelling, crusting, bleeding and signs of inflammation, opacity on sinus X-ray films, and nasal flow as measured by rhinomanometry were all significantly better in the group inhaling brine solution (P less than 0.05).

Adolescent↗
PubMed1991

[Congenital cerebrospinal fluid pressure labyrinth].

The audiograms and CT scans of three children with a bilateral congenital mixed deafness are presented. Two children underwent an exploratory tympanotomy revealing a fixed stapes footplate: a perilymph gusher arose during platinotomy in both cases. The gusher was controlled successfully with a large fat graft in both children, and hearing remained unchanged. Two of the children were brothers: they had no other deformities except an enlarged fundus of the auditory canal on CT scans, and no clearly defined bony barrier to the vestibule, suggesting a cerebrospinal fluid fistula. Neither a patent nor an abnormal cochlear aqueduct could be detected in all three cases. It is likely that the three patients present an X-linked mixed deafness syndrome with fixation of the stapedial foot plate and perilymph gusher. A classification of congenital perilymph-CSF shunts is proposed.

Cerebrospinal Fluid Otorrhea↗
PubMed1991

[Hearing disorders following spinal anesthesia].

In the few case reports of hearing loss following spinal anesthesia, complete recovery of the hearing impairment has always been described. In nine cases with hearing loss following not only spinal anesthesia but also myelography and dural puncture, the hearing of three patients did not recover or only partly returned. Two cases went to court for malpractice. Their suits could be dismissed because it appears likely that this rare complication arises only in persons with a wholly or partially unobliterated aquaeductus cochleae due to loss of perilymphatic fluid into the cerebrospinal space. Hearing loss was seen in eight of nine patients in lower frequencies around 30-40 dB. In six patients there was impairment on both sides. Recovery of normal hearing occurred in six of the nine patients. Transient hearing loss may occur more often than is generally assumed, and the symptom may remain unnoticed when a severe post-dural puncture syndrome with headache, dizziness, and nausea dominates the attention of the patient. Not all cases of hearing loss proved to be fully reversible, but the individual risk for this complication is not predictable. The use of fine-gauge needles may reduce the leakage of cerebrospinal fluid through the dural puncture and thus lower the incidence.

Adult↗
PubMed1990

Malignant cell autolysis caused by intracytoplasmic liberation of lysosomal enzymes.

An ultrastructural study of the action of peptidoglycans on malignant lymphocytes was made. Glycans acted upon lysosomes labilizing and rupturing the lysosomal membrane. Lysosomal enzymes were discharged directly into the cell cytoplasm. Nucleus, mitochondria and all organelles were digested in situ, resulting in a completely structureless cell. Finally, cancerous cells disintegrated by the detachment of cytoplasmic fragments.

Animals↗
PubMed1990

[Hypoglossal nerve paralysis following tonsillectomy].

Lesions of the lingual nerve and the glossopharyngeal nerve following tonsillectomy are rare but can be expected because of their anatomical course. What is extremely rare is a lesion of the hypoglossal nerve, whose course behind the carotid artery protects it from direct injury. The few cases described in the literature are thought to have been caused by inflammatory processes. It became necessary to look for other causes when, after a regular tonsillectomy, a hypoglossal palsy became evident in the absence of any inflammation. In an experiment, it was possible to demonstrate that both the insertion of a spatula and of an intubation spatula caused a strain of the hypoglossal nerve when the spatulas were inserted in the lateral lingual region. The nerve was distended by as much as 1.3 cm. The more the head was reclined, the more the nerve was distended. It would seem probable that this extension of the hypoglossal nerve causes its palsy following tonsillectomy.

Adult↗
PubMed1990

[Inner ear hearing loss following cerebrospinal fluid puncture: a too little appreciated complication?].

Lumbar puncture for myelography, spinal anaesthesia and aspiration of cerebrospinal fluid is a very common procedure. Although it has been known for a long time that hearing impairment may be a late complication, only a few case reports have been published, and not all have included audiograms. We present nine cases of hearing loss following myelography, lumbar puncture and spinal anaesthesia. It appears likely that this rare complication arises only in subjects with a wholly or partially patent cochlear aqueduct, allowing loss of perilymphatic fluid into the cerebrospinal space. Hearing loss was seen in eight of nine patients in the lower frequencies and in six of nine patients on both sides. Hearing recovered in six of nine patients. Transient hearing loss may occur more often than is generally assumed, and the symptom can remain unnoticed. Since not all of these hearing losses proved to be fully reversible, we suggest to inform patients about this complication for medico-legal reasons.

Adult↗
PubMed1989

Effect of inhaled endotoxin on bronchial reactivity in asthmatic and normal subjects.

Endotoxins are released from the membrane of Gram-negative bacteria present in the environment and in oral and nasal cavities. They are proinflammatory substances that could participate in bronchial obstruction and hyperreactivity in asthmatic patients. This hypothesis was tested by using bronchial challenge tests with inhaled lipopolysaccharides (LPS) from Escherichia coli 026:B6 (22.2-micrograms total dose) followed by a histamine nonspecific challenge test and compared with a placebo procedure, in which the diluent was substituted for the LPS solution. In doing so we showed that LPS induces a slight but significant (P less than 0.01) bronchial obstruction (measured as forced expiratory volume in 1 s) in asthmatics (n = 8) but not in normal subjects (n = 6). The histamine hyperresponsiveness, expressed as the dosage of histamine necessary to decrease the bronchial specific conductance by 50%, was increased 5 h after LPS inhalation in asthmatics (P less than 0.05) but not in normal subjects. This effect of LPS on bronchial obstruction and hyperresponsiveness was observed in extrinsic (n = 6) as well as in intrinsic (n = 2) asthma.

Administration, Inhalation↗