[Electroencephalograms (EEG) in 250 patients with epilepsy in a cysticercosis endemic area in Burundi]. / Electroencéphalogrammes réalisés chez 250 patients épileptiques dans une zone d'endémie cysticerquienne au Burundi.

OBJECTIVES: This work aimed at describing EEG abnormalities in epileptic patients living in areas endemic for cysticercosis, underlining the electroclinical correlations and discussing the interest of EEG examination in this context. METHODS: During a case-control study, 250 EEGs from patients with epilepsy were recorded with a portable system. Types of seizures were assessed clinically and from information obtained through a standardised questionnaire, and along with EEG were related to the results of cysticercosis serological tests. RESULTS: Among the 249 EEGs, 48% were normal, 5.2% had epileptic abnormalities, 6.8% showed an association between epileptic abnormalities and slow alterations. Slow theta and delta abnormalities were found in 21.8% of cases, and isolated deterioration of basic rhythms was observed in 17.3% of cases. Most seizures were generalized, and 61% of the patients had positive serology. One EEG was uninterpretable and another showed isolated spikes. Electroclinical agreement was considered to be satisfactory in 33 patients, and was better with the epileptic than with slow abnormalities. The existence of epileptiform EEG abnormalities confirmed clinically diagnosed epilepsy, but did not allow etiological diagnosis. Electroserological agreement was good in 24 patients. A significant association (Chi2, p = 0.03) existed between slow focal abnormalities and positive cysticercosis serology. Conversely, no significant association was detected between epileptic patterns and serology results. CONCLUSION: While the EEG alone clearly does not allow aetiological diagnosis, its joint use with clinical and biological results was a key element of the etiological and therapeutic discussion. When it shows focal abnormalities in a patient with epilepsy living in a high prevalence cysticercosis area, it confirms the clinical suspicion of neurocysticercosis. Morphological imagery alone can provide etiological information on the seizures by showing the nature and localization of the parenchymal lesions.

[Comparison of sociocultural attitudes towards epilepsy in Limousin (France), in Togo and in Benin (Africa)]. / Comparaison des représentations socioculturelles des épilepsies en Limousin (France), au Togo et au Bénin (Afrique).

Sociocultural attitudes continue to have a negative impact on management of epilepsy in many African countries and in a few advanced countries. The purpose of this study was to compare attitudes toward epilepsy in France and two African nations: Togo and Benin. A total of 305 epileptic patients over 18 years of age were interviewed using the same quantitative questionnaire about their beliefs, knowledge attitudes and practices regarding their disease. There were 77 patients from the Limousin region in France, 129 from the rural canton of Nadoba in Togo and 99 from the coastal province in Benin. The frequency of epileptic seizure during the last two years prior to the study was lower in France than in Togo and Benin. The number of people who believed in supernatural causes of epilepsy was higher in Togo and Benin whereas the number of people attributing the disease to social causes (e.g. death and stress) was higher in France. Few epileptic patients in France thought that the disease was contagious whereas many patients in both Togo and Benin still believed that the disease was contagious and that some foods were forbidden. More patients in France than in Togo and Benin were aware of the relationship of epilepsy with alcohol, drug abuse and cerebral injury. Epileptic patients in France were more likely to consult a physician and use medical drugs for the treatment of epilepsy than their counterparts in Togo and Benin. Epileptic patients in Togo often complained of social exclusion. Although sometimes contradictory, these findings support the idea that sociocultural attitudes should be taken into account in the management of the disease.

Is the morning peak of acute myocardial infarction's onset due to sleep-related breathing disorders? A prospective study.

Many studies have shown that the risk of experiencing a myocardial infarction (MI) is increased during the first hours of the morning. Sleep apnea syndrome (SAS) is associated with an enhanced adrenergic activity, prolonged a few hours after awakening. We aimed at assessing whether sleep breathing disorders could be a culprit for the morning excess rate of MI. We studied 40 middle-aged men admitted for an acute MI. An overnight polysomnographic study was performed 37.4 +/- 9.4 days after the MI. The prevalence of SAS was high (30%). The prevalence of SAS was significantly higher in patients with the MI onset during the morning. The circadian pattern was significantly different in patients with or without SAS: those with SAS presented an important peak of MI onset during the period between 06.00 and 11.59 h. None of them had their MI during the period between 24.00 and 05.59 h. This different nyctohemeral pattern underlines the potential role of sleep breathing disorders as a trigger of MI.

Reversal of the sleep/wake cycle disorder of sleeping sickness after trypanosomicide treatment.

To determine whether the circadian disruption of the sleep/wake cycle observed in sleeping sickness, human African trypanosomiasis (HAT), can be reversed after trypanosomicide treatment, 10 Congolese patients infected by Trypanosoma brucei gambiense underwent 24-h polysomnographic recordings before treatment with melarsoprol and after each of three weekly treatment sessions. Polysomnography consisted of a continuous recording of the electroencephalogram, electromyogram and electro-oculogram on a Minidix Alvar polygraph. Sleep traces were analysed in 20-sec epochs for wakefulness, REM sleep, and NREM sleep [stages 1, 2, 3, 4; stages 3 and 4 representing slow-wave sleep (SWS)]. As previously described (Buguet et al. 1993), the 24-h distribution of the sleep/wake cycle was disturbed proportionally to the severity of the illness. The overall amounts of each sleep/wake stage did not change after treatment. However, the patterns of occurrence of sleep episodes, REM sleep and SWS phases were determinant in the evaluation of treatment efficacy. The trypanosomicide action of melarsoprol led to a reduction in the number of sleep episodes, except in one patient whose health condition worsened during the third treatment session: sleep onset REM sleep phases (SOREMPs) decreased and the number of SWS episodes during a sleep episode increased. We conclude that in HAT, the reversibility of the sleep/wake cycle alteration and that of sleep structure constitute the basis for an evaluation of the healing process.

Sleep apnoea syndrome and the extent of atherosclerotic lesions in middle-aged men with myocardial infarction.

BACKGROUND: To determine whether extended atherosclerotic lesions are correlated to the presence of sleep breathing disorders. EXPERIMENTAL DESIGN: A prospective clinical study. SETTING: A tertiary regional referral center. PATIENTS: 40 male patients < or =65 years consecutively admitted to the cardiac care unit for an acute myocardial infarction with serous creatinine phosphokinase (CPK) > or =350 IU/l and a CPK-MB fraction > or =10%. Exclusion criteria were: cardiac surgery on emergency, stroke, major neurological and/or psychiatric disturbances, alcohol consumption >50 g/day, toxicomania, clinical or biological hypothyroidism, clinical acromegaly and chronic obstructive pulmonary disease. MEASURES: Duplex ultrasonography was performed on carotid arteries, femoral arteries and their bifurcations. An overnight polysomnography was performed after hospital discharge. Patients with an apnoea index >5/hour or apnoea-hypopnea index >10/hour of sleep are considered to have sleep apnoea syndrome (SAS). Patients with additive peripheral atherosclerotic lesions are compared to patients with normal carotid and femoral arteries, regarding to standard cardiovascular risk factors and apnoeas or hypopnoeas during sleep. RESULTS: Duplex revealed in 18 patients carotid and/or femoral atherosclerotic lesions. The prevalence of SAS in patients with at least one peripheral arterial lesion was significantly higher (61% vs 18%, p<0.01). A nearly significant difference was also noted in patients with carotid lesions alone compared to those with normal carotid arteries (57% vs 27%, p=0.06). CONCLUSIONS: These results suggest a possible link between sleep breathing disorders and the pathogenesis of atherosclerotic lesions.

Eyelid hyperlaxity and obstructive sleep apnea (O.S.A.) syndrome.

PURPOSE: An association between the floppy eyelid syndrome and the obstructive sleep apnea syndrome (O.S.A.) has been reported. We studied eyelid tissue elasticity and other ophthalmologic findings in a large number of patients with sleep disorders. MATERIAL AND METHODS: Sixty-nine patients with sleep disorders were evaluated. Two thirds were found to have O.S.A., and one third was treated at night by nasal continuous positive airway pressure (nasal C.P.A.P.). Slit lamp examination, eyelid measurements and Schirmer test were performed. RESULTS: Eyelid hyperlaxity was increased in patients with O.S.A. The floppy eyelid syndrome (associated papillary conjunctivitis), however, was rare. Associated corneal lesions were rare, and most patients were asymptomatic. In some cases, ocular irritation was due to air leaks from nasal C.P.A.P. A significant proportion of patients required treatment for primary open angle glaucoma. CONCLUSIONS: Our study of 69 patients found an association between O.S.A. and eyelid hyperlaxity.

Electroencephalographic and polygraphic features of 24-hour recordings in sleeping sickness and healthy African subjects.

Electroencephalographic (EEG) and polygraphic features were analysed in six healthy control subjects and eight patients suffering from sleeping sickness meningoencephalitis in order to determine possible functional relationships. One patient was disqualified because of intermittent metabolic disease. Twenty-four h polygraphic recordings-EEG, electrooculography (EOG), electromyography (EMG), nasal and buccal air flow, chest respiratory movements-were performed continuously both on paper and on cassette tapes. Tapes were played back on paper (paper speed: 15 mm/s). Traces were analyzed for normal and pathologic features, and transient activation phases and paroxysmal hypnopompic hypersynchrony events were counted. During wakefulness, slow theta and delta waves occurred in four patients, but alpha reactivity was present. During sleep, normal features were seen. However, transient activation phases were decreased in the patients. During slow-wave sleep, four patients presented predominantly monophasic frontal delta bursts along with paroxysmal hypnopompic hypersynchrony events. In conclusion, in sleeping sickness patients, although dampened, the waking process remains responsive and slows down only during the late stage of meningoencephalitis.

Relationship of plasma growth hormone to slow-wave sleep in African sleeping sickness.

Human African trypanosomiasis (sleeping sickness) is a unique disease model of disrupted circadian rhythms in the sleep-wake cycle and cortisol and prolactin secretion. This study examined the temporal relationship between growth hormone (GH) secretion and the sleep-wake cycle in 8 infected African patients and 6 healthy indigenous African subjects. Twenty-four-hour sleep patterns were recorded by polysomnography and hourly blood samples analyzed for plasma GH. No relationships between the mean normalized plasma GH levels (Z scores) and the sleep stages (wakefulness, sleep stages 1 and 2 ('light' sleep), slow-wave sleep (stages 3 and 4, SWS), and rapid eye movement (REM) sleep) were found in the patients or healthy subjects. However, when the time of sampling of the plasma GH concentrations was lagged by 16 min with respect to the occurrence of the various sleep stages, significant correlations were found between plasma GH concentrations and SWS in both healthy subjects and patients. Thus, the association between SWS and GH secretion persisted even in the presence of disrupted circadian rhythms, further supporting the concept that sleep and the stimulation of GH secretion are outputs of a common mechanism.

Twenty-four-hour plasma cortisol and prolactin in human African trypanosomiasis patients and healthy African controls.

We have previously demonstrated that human African trypanosomiasis (sleeping sickness) at the stage of meningoencephalitis results in a major disruption of the circadian rhythmicity of sleep and wakefulness that is proportional to the severity of the disease. This paper examines the corresponding 24-hourly secretion in cortisol and prolactin and compares it with the hourly distribution of sleep composition in infected patients and healthy African subjects. The secretion of cortisol in humans follows a circadian rhythm relatively independent of the sleep-wake cycle, whereas that of prolactin exhibits fluctuations over the 24-hr day that are strongly related to the sleep-wake cycle. After the clinical classification of the patients according to the severity of the disease, hourly blood samples were taken over 24 hr via an indwelling catheter. Plasma cortisol and prolactin were analyzed by radioimmunoassay, and the variations in the hourly concentrations were analyzed for the presence of a potential 24-hr rhythm (circadian). All of the healthy African subjects showed significant circadian rhythms in both cortisol and prolactin secretion, similar to data on humans from temperate regions, and a sleep-related anamnestic afternoon peak of prolactin. Major disruptions in the circadian rhythms of plasma cortisol and prolactin were found in the three patients with the most severe illness, in contrast to the four who were less severely ill and the healthy controls. Thus, it appears that as the disease progresses in severity, major disruptions begin to occur in body circadian rhythms, not only in the sleep-wake cycle as reported elsewhere, but also in cortisol and prolactin secretion, suggesting that sleeping sickness affects the circadian timing system.

[The distribution of sleep and wakefulness in human African trypanosomiasis]. / Distribution du sommeil et de la veille dans la trypanosomose humaine africaine.

Last century, patients with human African trypanosomiasis were described as sleepy by day and restless by night, and physicians referred to this condition as sleeping sickness. Such a description could have evoked a disturbance of circadian rhythms. However, it is only in 1989 that the first 24-hour recording was performed by our team in Niamey (Niger) in a patient with sleeping sickness. The patient was a Niger-born farm worker who had contracted the disease near Gagnoa (Côte d'Ivoire). Polysomnographic recordings (electroencephalogram, EEG, electrooculogram, electromyogram, electrocardiogram, buccal and nasal airflow, and chest respiratory movements) showed a disappearance of the circadian distribution of sleep and wakefulness, which tended to occur evenly throughout day and night, with a sleep-wake alternation of approximately 80 minutes. Two investigations were conducted thereafter. The first one was done at Daloa (Côte d'Ivoire) in 8 patients who were recorded during two 24-hour periods, with and without hourly blood samples; the second at Brazzaville (Congo) in 10 patients recorded for 24 hours before and after treatment with melarsoprol. All patients were at the stage of early meningoencephalitis. At Daloa, polysomnographic recordings were taken on two 8-channel EEG machines (Alvar Minihuit, and T3-ECEM), as well as on a portable Oxford Medilog 9000 system from the same electrodes. Sleep and wake structure was altered in the most severely sick patient, the EEG trace being loaded with slow waves. Stages 1 and 2, and stages 3 and 4 could not be distinguished from one another. In the other patients, all sleep stages were easily scored. No difference was seen between recordings, regarding blood collection.(ABSTRACT TRUNCATED AT 250 WORDS)

Disruptions in the secretion of cortisol, prolactin, and certain cytokines in human African trypanosomiasis patients.

It has been shown previously that sleeping sickness at the stage of meningoencephalitis manifests itself as a significant disturbance in the circadian rhythm of sleep-wakefulness. The objective of the current study was to examine the extent of circadian disruption in infected patients by measuring 24 hours patterns of plasma cortisol, an example of a classical circadian rhythm relatively independent of sleep, and prolactin, a primarily sleep-related rhythm. Plasma levels of certain cytokines were also measured to examine the immunopathogenesis of human African trypanosomiasis. An attempt was made to relate any circadian disruptions to the severity of the disease. The three most advanced patients demonstrated circadian disruptions in cortisol, prolactin and sleep-wake rhythms. The prime cytokine factor that correlated with the progression of the disease in humans was interferon-gamma, levels being 7- to 12-fold higher in the patients without any circadian rhythms. Our findings support the hypothesis that human African trypanosomiasis induces selective changes in the suprachiasmatic nucleus, important as a pacemaker for biological rhythms, resulting in disruptions of circadian rhythmicity in advanced stages of the disease.

Sleep-wake cycle in human African trypanosomiasis.

Sleeping sickness patients are classically described as sleepy by day and restless by night. Prior to this study, we had objectively confirmed this description by recording 24-h sleep patterns in a patient with human African trypanosomiasis. We report 24-h polysomnographic recordings (EEG, electrooculogram, electromyogram, electrocardiogram, and nasal, buccal, and thoracic respiratory traces) performed on two eight-channel electroencephalographs in eight patients with untreated sleeping sickness at an early stage of meningoencephalitis. As in our previously reported patient, there was no hypersomnia. The patients presented mainly a disorganization of the circadian alternation of sleeping and waking, with no or little alteration in the states of vigilance at this early stage of the disease. The disorganization was proportional to the degree of severity of the clinical symptoms. It may be due to an alteration in biological clock mechanisms.

Study of evoked potentials in human African trypanosomiasis.

Human African trypanosomiasis or sleeping sickness has a stage of neurological involvement characterized by the onset of diffuse meningoencephalitis with sleep disturbances and decreased wakefulness. The pathogenesis of this disease is not well understood. We studied auditory, visual, sensory, and motor evoked potentials in 16 patients with trypanosomiasis in the early stage of meningoencephalitis. In all patients, the brain-stem auditory evoked response (BAER) and the pattern-reversal visual evoked response (PVER) were normal. On the other hand, abnormalities of the somatosensory evoked response (SSER) or the motor evoked response (MER) were found in only five cases; however, their relationship to the illness could not be definitely confirmed. The study results indicate that the evaluated pathways were essentially intact, in particular at the level of the brain-stem in the early stage of the disease. Sleep disturbances and decreased wakefulness noted at this stage were thus linked more closely to functional involvement at the level of the sleep centres than to any detectable specific anatomic lesion.

[Circadian analysis of sleep, rectal temperature and immunological and endocrinological variables in sleeping sickness: preliminary study]. / Analyse circadienne du sommeil, de la température rectale et de variables immunologiques et endocrinologiques dans la maladie du sommeil: etude préliminaire.

A multidisciplinary study was conducted in 8 patients with neurological Human African Trypanosomiasis. The sleep-wake cycle followed an ultradian pattern which was more pronounced in patients with more severe symptoms. The EEG trace was consistently interrupted by numerous cyclic activation patterns with K complexes, rapid low amplitude elements and slow high voltage elements. Circadian rhythmicity was also disturbed in other physiological (rectal temperature), immunological (interleukins) or hormonal (cortisol, prolactin) variables, the disturbance being greater in severely hit patients.

Comparison of the Oxygen Exchange between Photosynthetic Cell Suspensions and Detached Leaves of Euphorbia characias L.

Using a mass-spectrometric (16)O(2)/(18)O(2)-isotope technique, we compared the nature and the relative importance of oxygen exchange in photomixotrophic (PM) and photoautotrophic (PA) suspensions of Euphorbia characias L. with those in intact leaves of the same species. Young and mature leaves, dividing and nondividing cell suspensions were characterized in short-term experiments. On chlorophyll basis, the gross photosynthetic activities at CO(2) saturating concentration of PA and PM suspensions varied little from those of leaves. On dry weight basis, gross photosynthesis of PA suspensions was equal to that of leaves because of their similar chlorophyll content. This was not the case in PM suspensions where gross photosynthesis was lower and largely varied during the growth cycle. The CO(2) compensation point of PA cells (155-265 parts per million) was much higher than that of leaves (50-80 ppm). Oxygen uptakes were analyzed in terms of mitochondrial respiration, photorespiration and light stimulation of oxygen uptake (LSOU), often identified to Mehlertype reactions. In PA and PM suspensions, mitochondrial respiration rates were higher than in leaves by a factor of 1.5 to 4.5. In PM suspensions, photorespiration and LSOU were observed only in nondividing cells. Photorespiration and LSOU rates were comparable in PA suspensions and leaves. Our results demonstrate that photorespiration of PA suspensions has not been affected by the 2% CO(2) concentration imposed during 2 years of culture.

Microalgae production: technical and economic evaluations.

A review of the various literature data for large-scale algae production costs is described. Costs were updated and recomputed in order to compare the different schemes. Total production costs of a nonprocessed biomass range from US$0.15 to US$4.0 kg(-1), according to various authors. Process performance hypotheses and proposed technologies are analyzed to explain these variations. A cost analysis for a tubular bioreactor system is then presented that shows that, assuming a productivity of 60 tons/ha yr, production costs would range from FF24 to FF29 kg(-1) for such a system. Operating costs as well as fixed charges account for approximately 50% of the cost. Parametric sensitivity of these costs is then analyzed: If productivity would be 30, 45, or 90 tons/ha yr, total cost would be around FF48, FF33 and FF19 kg(-1). Advantages and disadvantages of the proposed tubular technology are finally discussed.

Mass spectrometric determination of the inorganic carbon species assimilated by photoautotrophic cells of Euphorbia characias L.

The chemical forms of inorganic carbon, CO2 or HCO3-, incorporated during photosynthesis in photoautotrophic Euphorbia characias cell suspension cultures were determined in experiments using 13CO2 and a mass spectrometry technique. From the equations of the CO2 hydration reaction, a kinetic model was first developed, and the effect of photosynthesis on the external CO2 concentration was simulated. It was predicted from this model that CO2 and HCO3- uptakes could be differentiated by recording only the CO2 variation rate in the external medium, successively in absence then in presence of an exogenous carbonic anhydrase activity. The results obtained with either CO2-grown or air-grown photoautotrophic cells were in good agreement with the model and demonstrated that CO2 was the sole species taken up during photosynthesis. In addition no accumulation of inorganic carbon within the cells was observed in the light. Similarly, in dark, CO2 was the only species released by respiration in the external medium.

[Early auditory evoked potentials in normal sheep and in sheep with trypanosomiasis]. / Potentiels évoqués auditifs précoces chez le mouton sain et chez le mouton trypanosomé.

In human and animal clinics, the early auditory potential has been used for a long time in the detection of lesions through the internal auditory way in the cerebral trunk. The aim of this work tries to determine if this non invasive test is apt to show up and to follow the evolution of lesions at the level of auditory way in the cerebral trunk of sheep with trypanosomiasis. According to the human technic, the list of the early auditory potential was realized against ten healthy sheep and ten sheep with trypanosomiasis (Trypanosoma brucei brucei) at the nervous phase. No significant anomalies exist in the sheep with trypanosomiasis. The results are discussed.