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Biomedical subjects

G Aubert-Tulkens

Publications and source records attributed to G Aubert-Tulkens.

At least 19 recordsLinked to original sources
PubMed1993

Rabies encephalitis mimicking the electrophysiological pattern of brain death. A case report.

A 48-year-old woman was referred from Zaire with suspected rabies encephalitis. Survival was 34 days after the onset of symptoms and the diagnosis of rabies was ultimately proven after brain autopsy. Serial neurophysiological investigations, including EEG and multimodality evoked potentials and radiological examinations (cerebral magnetic resonance imaging and computed tomodensitometry) were performed. Whereas the clinical findings and EEG were compatible with brain death at the end of the course, this diagnosis could be definitely ruled out by multimodality evoked potentials, magnetic resonance imaging and autopsy. The validity of multimodality evoked potentials is discussed in this particular setting.

Brain↗
PubMed1992

Diurnal and nocturnal diuresis and natriuresis in obstructive sleep apnea. Effects of nasal continuous positive airway pressure therapy.

Excessive nocturnal diuresis and natriuresis have been reported in patients with sleep apnea. The mechanisms responsible for these alternations in nocturnal renal function have not been clearly identified. To gain further insight into this matter, we studied 12 patients (one woman) with a mean +/- SD age of 50 +/- 9 yr and body mass index of 36.9 +/- 8.6 kg/m2. Polysomnography showed in all a sleep apnea syndrome with an apnea-hyponea index (AHI) of 81.3 +/- 41.7. Treatment with nasal continuous positive airway pressure (nCPAP) resulted in an AHI of 19.4 +/- 13.7 and in normalization of sleep characteristics. Diurnal renal function was normal in all subjects. Although untreated, patients showed an abolition of the well-known decrease in diuresis and natriuresis during the night (diurnal and nocturnal diuresis 56.3 +/- 26.8 and 77.2 +/- 33.4 ml/h, respectively, p = NS; diurnal and nocturnal fractional urinary Na+ excretion 0.42 +/- 0.09 and 0.70 +/- 0.55 ml/100 ml glomerular filtration [GF], respectively, p = NS). Results of nocturnal studies under nCPAP therapy showed a significant decrease in diuresis and natriuresis (nocturnal diuresis before and under nCPAP, respectively: 90.4 +/- 27.3 and 70.6 +/- 25.1 ml/h, p less than 0.02; nocturnal fractional urinary sodium excretion before and under nCPAP, respectively: 0.76 +/- 0.53 and 0.44 +/- 0.37 ml/100 ml GF, p less than 0.03). Morning blood levels of renin, aldosterone, antidiuretic hormone, epinephrine, and atrial natriuretic factor showed no significant difference before and under nCPAP, whereas norepinephrine significantly decreased from 309.5 +/- 104.2 before to 230.4 +/- 88.4 pg/ml under nCPAP (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian Rhythm↗
PubMed1991

Upper airway obstruction during nasal intermittent positive-pressure hyperventilation in sleep.

Episodes of apnoea for up to 1 min were observed in association with hypocapnia caused by passive nasal intermittent positive-pressure mechanical hyperventilation in 3 of 4 patients during sleep. Apnoea seemed to be caused by complete upper airways obstruction; we suggest that this finding was caused by active glottic closure. Avoidance of excessive hypocapnia during positive-pressure ventilation might help to avoid central-nervous-system mediated apnoeic episodes.

Adult↗
PubMed1991

Pattern of snoring in obstructive sleep apnea patients and in heavy snorers.

We measured respiratory mechanical characteristics during sleep in five heavy, nonapneic snorers (HS) and in five obstructive sleep apnea (OSA) patients. In two HS and in two OSA patients we obtained lateral pharyngeal cineradiographic images during sleep while snoring. Flow limitation preceded all snores in both HS and OSA. Pattern of snoring, hysteresis and temporal relationship between supraglottic pressure (Psg) and flow rate were different in HS and OSA. Maximal flow during snoring was less (p less than 0.05) in OSA (0.18 +/- 0.07 liter/second) than in HS (0.36 +/- 0.06 liter/second). Linear supraglottic resistance during inspiratory snoring was higher, though not significantly, in OSA patients (7.11 +/- 3.01 cm H2O/liter/second) than in HS (4.80 +/- 2.83 cm H2O/liter/second). We conclude that: 1) Snoring is characterized by high frequency oscillations of the soft palate, pharyngeal walls, epiglottis and tongue. 2) Flow limitation appears to be a sine qua non for snoring during sleep. 3) The pattern of snoring is different in OSA and HS. 4) Pharyngeal size during snoring is probably larger in HS than in OSA patients.

Adult↗
PubMed1990

Pharyngeal shape and dimensions in healthy subjects, snorers, and patients with obstructive sleep apnoea.

To characterise the relation between pharyngeal anatomy and sleep related disordered breathing, 17 men with complaints of snoring were studied by all night polysomnography. Ten of them had obstructive sleep apnoea (mean (SD) apnoea-hypopnoea index 56.3 (41.7), age 52 (10) years, body mass index 31.4 (5.3) kg/m2); whereas seven were simple snorers (apnoea-hypopnoea index 6.7 (4.6), age 40 (17) years, body mass index 25.9 (4.3) kg/m2). The pharynx was studied by magnetic resonance imaging in all patients and in a group of eight healthy subjects (age 27 (6) years, body mass index 21.8 (2.2) kg/m2, both significantly lower than in the patients; p less than 0.05). On the midsagittal section and six transverse sections equally spaced between the nasopharynx and the hypopharynx several anatomical measurements were performed. Results showed that there was no difference between groups in most magnetic resonance imaging measurements, but that on transverse sections the pharyngeal cross section had an elliptic shape with the long axis oriented in the coronal plane in normal subjects, whereas in apnoeic and snoring patients the pharynx was circular or had an elliptic shape but with the long axis oriented in the sagittal plane. It is suggested that the change in pharyngeal cross sectional shape, secondary to a reduction in pharyngeal transverse diameter, may be related to the risk of developing sleep related disordered breathing.

Adult↗
PubMed1990

Hypopharyngeal and neck cross-sectional changes monitored by inductive plethysmography.

We present a method to assess cross-sectional area (CSA) changes of the extrathoracic airways (EA) by using an inductive plethysmograph (IP) band placed around the upper part of the neck. Measurements of mouth pressure (Pm) (or flow rate, V) and neck CSA changes during respiratory efforts against a high (or infinite) resistance have shown a highly significant relationship between Pm changes (or V changes, respectively), reflecting CSA changes of the EA and CSA changes of the neck. Simultaneous measurements of CSA of the neck (by IP) and of EA (by computerized tomography) during sustained inspiratory and expiratory efforts against a closed airway showed a high correlation between changes in the former and latter structures. Changes in CSA of the neck were larger with positive than negative transmural pressures, in keeping with the known larger compliance of this airway during expiration. We found this method helpful to assess the behavior of the EA during obstructive apnea episodes, hypopneas, and snoring.

Adult↗
PubMed1989

Cure of sleep apnea syndrome after long-term nasal continuous positive airway pressure therapy and weight loss.

Two male patients [aged 53 and 54 years; body mass index (BMI) of 36.8 and 34.4 kg/m2] presented with severely symptomatic sleep apnea syndrome. Polysomnographic recording showed sleep fragmentation, diminution of stages III and IV and continuous sleep-related disordered breathing with mixed and obstructive apneas and hypopneas, and snoring. Apnea index (number of apneas per sleep-hour) was 73 and 30, respectively. These abnormalities were reversed by nasal continuous positive airway pressure (nCPAP). Home treatment with nCPAP associated with hypocaloric diet was started. Six months later, all symptoms had disappeared and BMI was 29 and 29.2 kg/m2, respectively. Polygraphic recordings without nCPAP showed regular breathing in all sleep stages, which were stable and normally abundant. Therapy has been discontinued and clinical and polygraphic data have remained normal for up to 6 and 11 months, respectively.

Arousal↗
PubMed1989

Adaptation to intermittent positive pressure ventilation applied through the nose during day and night.

A 49 yr old poliomyelitic patient had been under cuirass-type nocturnal negative pressure ventilation for more than 20 yrs. He had a severe restrictive ventilatory impairment, and normal awake blood gases at rest and during light exercise. He was offered a trial of intermittent positive pressure ventilation applied through the nose (nIPPV). Two daytime studies and one night study were carried out under nIPPV, and one night study was performed under negative pressure ventilation. Tidal volume, respiratory frequency (Respitrace), blood gases and electromyogram (EMG) of the diaphragm (DEMG, oesophageal electrode) and/or sternocleidomastoid (ScEMG, surface electrodes) were measured. During daytime studies under nIPPV, the DEMG (and/or the ScEMG) did not decrease by more than 25% (p less than 0.005). However, when the patient was encouraged to relax, the DEMG decreased by 62% (p less than 0.001). Tidal volume and ventilation significantly increased during daytime nIPPV (p less than 0.025), whereas blood gases were kept at physiological levels. At night, the ScEMG was present and prominent until sleep onset. Thereafter it disappeared and remained silent, including periods of wakefulness during sleep time, until final awakening in the morning. This was true for both negative pressure ventilation and nIPPV. Snoring was present throughout sleep under negative pressure ventilation but not under nIPPV. We conclude that the behavioural response of the subject may determine the electrical activity of respiratory muscles during assisted ventilation.

Adaptation, Physiological↗
PubMed1989

Failure of tonsil and nose surgery in adults with long-standing severe sleep apnea syndrome.

Seven adult patients with a severe form of sleep apnea syndrome (mean apnea index, 47) underwent surgery for significant structural abnormalities at nose and/or throat level (septal deviation, turbinal hypertrophy, enlarged tonsils, long uvula, pharyngeal tumor). Although a subjective benefit was claimed by most patients, the polygraphic data showed no improvement or only a modest improvement in breathing pattern, oxyhemoglobin saturation, or general sleep architecture except in one patient. In this patient the evolution of the syndrome was recent (3 years) and surgical management of a parapharyngeal tumor resulted in a cure. We conclude that in adults with sleep apnea syndrome of long-standing, surgical correction of nasal or pharyngeal abnormalities should not be expected to normalize sleep and breathing. This contrasts with the known benefits achieved by the same type of surgery in children. Surgery might nevertheless be necessary in some adults to permit the application of other therapeutic means (ie, nasal continuous positive airway pressure).

Adult↗
PubMed1987

Ambulatory evaluation of sleep disturbance and therapeutic effects in sleep apnea syndrome by wrist activity monitoring.

A new wrist actometer was used to obtain ambulatory activity-rest recordings in 18 patients with sleep apnea syndrome (SAS) and in 22 control subjects. A movement index (MI) and a fragmentation index (FI) during sleep time were computed, giving an estimate of the stability of sleep. In control subjects, we observed a clear differentiation between night and day activity levels. The distribution of MI and FI was very narrow, with a mean +/- SD of 13.9 +/- 5.4 and 16.1 +/- 5.8%. No correlation of MI and FI with body mass index, even in heavily obese subjects, was found; MI and FI decrease significantly with age. A diagnosis of SAS was made by standard all-night polysomnography. Patients with SAS had a significantly higher MI and FI than did control subjects (p less than 0.001). With respect to polysomnographic diagnosis of SAS, the sensitivity of activity recordings was 89%, whereas the specificity was 95%. Five patients were studied after treatment, and decreases in MI and FI at home were in good agreement with the improvement in their sleep as assessed clinically and by polysomnography. We conclude that this technique is useful for an objective measurement of sleep restlessness and fragmentation, and for a simple evaluation of therapeutic effects under real life conditions in SAS.

Adult↗
PubMed1983

[Joubert syndrome. Clinical and anatomo-pathologic study. Etiopathogenetic hypotheses].

Joubert's syndrome is characterized by an agenesis of the vermis and an unique respiratory abnormality consisting of bouts of extreme tachypnea and prolonged apneas. Three patients with this syndrome are reported with a polygraphic study and a recording of intracranial pressure in one of them and a pathological study in another. It is suggested that the agenesis of the vermis is caused by a prenatal hydrocephalus as is probably the case in the Dandy-Walker syndrome. A comparison is established between these two syndromes. The periods of tachypnea-apnea could represent the persistence of a fetal pattern of respiration with an excessive response to various stimuli, and might be explained by the delayed maturation of inhibitory mechanisms necessary for the establishment of the normal pattern of respiration and sleep. The possible role of a total vermian agenesis in the pathogenesis of respiratory abnormality is discussed.

Cerebellum↗
PubMed1979

Cellular toxicity of gentamicin.

Subconjunctival injections of gentamicin induced a lysosomal storage process within the conjunctival fibroblasts in rats, rabbits, and humans. Under electron microscopy, the accumulated substance was composed of a granular material and pleomorphic lamellar structures, corresponding to the presence of complex lipids. In animals, the other ocular tissues as well as the cells reached through the bloodstream remained unaffected, except the proximal convoluted tubules of the kidneys, where important lesions were evident. Although human kidneys were not examined in our study, we believe they might present similar alterations.

Animals↗