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Biomedical subjects

G Lavigne

Publications and source records attributed to G Lavigne.

At least 19 recordsLinked to original sources
PubMed2003

Age and gender effects on heart rate activation associated with periodic leg movements in patients with restless legs syndrome.

OBJECTIVE: Periodic leg movements during sleep (PLMS) are often associated with electroencephalographic (EEG) changes, such as microarousals (MA), and with heart rate (HR) variations. The aim of the present study was to evaluate the effects of age and gender on HR changes associated with PLMS in restless legs syndrome (RLS) patients. METHODS: Forty-two RLS patients underwent one night of polysomnographic recordings. They were divided into 3 groups of 14 subjects (7 women and 7 men) according to age, i.e. young (25-40 years), middle-aged (41-55 years) and elderly (56-71 years) patients. The RR interval was calculated for 5 intervals before and 15 intervals after the onset of 50 PLMS in each patient. RESULTS: PLMS were associated with HR changes characterized by a tachycardia followed by a bradycardia. However, a reduction in the tachycardia and the bradycardia was observed with age. Moreover, women showed a higher amplitude in the bradycardia than men. No age or gender difference was found for MA index and duration. CONCLUSIONS: This study showed age and gender differences in the magnitude of the HR changes associated with PLMS. The knowledge of HR variations during sleep, including rapid HR changes associated with sleep events such as PLMS or MA, may be helpful in understanding the potential mechanisms involved in the increased cardiac risk observed in elderly.

Adult↗
PubMed2003

Thrombophilic families with inheritably associated high levels of coagulation factors VIII, IX and XI.

We describe six families in which associated high levels of coagulation factors (F) XI, FIX and FVIII (each with a plasma concentration higher than the 95th percentile found in a control group of 500 asymptomatic individuals: respectively, 135, 145 and 155 IU dL-1) were inherited as a dominant autosomic genetic traits. In these six families, this syndrome is associated with venous thromboembolic events (Odds ratio 41 [4.9-353], P = 0.0006). It seems to predispose to idiopathic events and, as age increases, is often associated with recurrence. First thrombotic episodes occur in young patients (50% of the carriers are symptomatic at the age of 32 years) and in women, can be unmasked by hormonal treatments, mainly oral contraceptives. The association of high levels of coagulation FXI, FIX and FVIII is thus a new rare high-risk inherited thrombophilia syndrome.

Adolescent↗
PubMed2002

Periodic leg movements in REM sleep behavior disorder and related autonomic and EEG activation.

OBJECTIVE: To assess the frequency of periodic leg movements (PLM) in idiopathic REM sleep behavior disorder (RBD) and to analyze their polysomnographic characteristics and associated autonomic and cortical activation. BACKGROUND: PLM during sleep (PLMS) and wakefulness (PLMW) are typical features of restless legs syndrome (RLS), but are also frequently observed in patients with RBD. METHODS: Forty patients with idiopathic RBD underwent one night of polysomnographic recording to assess PLMS frequency. PLM features, PLMS-related cardiac activation during stage 2 sleep, and EEG changes were analyzed in 15 of these patients with RBD. Results were compared with similar data obtained in 15 sex- and age-matched patients with primary RLS. RESULTS: Twenty-eight (70%) of 40 patients with RBD showed a PLMS index greater than 10. No between-group differences were found in sleep architecture or indexes of PLMW and PLMS during non-REM sleep, but a trend for a higher PLMS index during REM sleep was found in patients with RBD. PLM mean duration and interval in the two conditions were similar. A transient tachycardia followed by a bradycardia was observed in close association with every PLMS in both groups, but the amplitude of the cardiac activation was significantly reduced in patients with RBD. In addition, significantly fewer PLMS were associated with microarousal in this condition. CONCLUSIONS: Periodic leg movements are very common in idiopathic RBD, occurring in all stages of sleep, especially during REM sleep. In idiopathic RBD, the reduction of cardiac and EEG activation associated with PLMS suggests the presence of an impaired autonomic and cortical reactivity to internal stimuli.

Aged↗
PubMed2002

Age difference in heart rate changes associated with micro-arousals in humans.

OBJECTIVES: Heart rate (HR) is known to change in association to micro-arousals (MA) during sleep. The aim of the present study was to evaluate the effect of age on HR variations associated with MA. METHODS: Thirty-two healthy subjects underwent one night of polysomnographic recording. They were divided into two groups of 16 subjects according to age i.e. young (20-35 years) and middle-aged (50-65 years). The R-R intervals were calculated for 11 heart beats (10 intervals) before and 15 heart beats after the onset of MA. RESULTS: HR changes associated with MA were characterized by a tachycardia followed by a bradycardia in both young- and middle-aged subjects. However, middle-aged subjects showed a significant reduction in the amplitude of both tachycardia and bradycardia as compared to young subjects. CONCLUSIONS: This study revealed an age-related reduction in the amplitude of the HR changes associated with MA. These results may reflect a decline in parasympathetic functions and a higher risk of cardiovascular diseases with advancing age.

Adult↗
PubMed2001

Formation of cyclopentadienyl and ruthenacyclopentadienyl derivatives through ynenyl-diyne and ynenyl-alkyne couplings onto a triruthenium cluster core.

The compound [Ru3(mu-H)(mu3-eta2-ampy)(CO)9] (1; Hampy =2-amino-6-methylpyridine) reacts with diynes RC4R in THF at reflux temperature to give the ynenyl derivatives [Ru3(mu3-eta2-ampy)(mu-eta3-RC...CC-CHR)(mu-CO)2-(CO)6] (2: R=CH2OPh; 3: R=Ph). These products contain a 1,4-disubstituted butynen-3-yl ligand attached to two ruthenium atoms. The compound [Ru3(mu-eta2-ampy)[mu3-eta6-PhCC5(C...CPh)-HPh2](CO)7] (4), which contains an eta5-cyclopentadienyl ring and a bridging carbene fragment, has also been obtained from the reaction of 1 with diphenylbutadiyne. This compound arises from a remarkable [3+2] cycloaddition reaction of a preformed 1,4-diphenylbutynen-4-yl ligand with a triple bond of a second diphenylbutadiyne molecule. The reactivity of the ynenyl derivatives 2 and 3 with diynes and alkynes has been studied. In all cases, compounds of the general formula [Ru3(mu-eta2-ampy)[mu3-eta5-C(=CHR)C=CRCR1=CR2](CO)7] (5-17) have been obtained. They all contain a ruthenacyclopentadienyl fragment formed by coupling of the coordinated ynenyl ligand of 2 (R = CH2OPh) or 3 (R = Ph) with a triple bond of the new reagent (the CR1=CR2 fragment results from the incoming diyne or alkyne reagent). While most of the products derived from 2 have the alkenyl C=CHR fragment with a Z configuration (R cis to Ru), all the compounds obtained from 3 have this fragment with an E configuration. Except 2 and 3, all the cluster complexes described in this article have a five-electron donor ampy ligand attached to only two metal atoms, a coordination mode unprecedented in cluster chemistry.

Journal Article↗
PubMed2001

Restless Legs Syndrome: scoring criteria for leg movements recorded during the suggested immobilization test.

Objective: To evaluate the characteristics of leg movements experienced by patients with the restless legs syndrome (RLS) during wakefulness using the suggested immobilization test (SIT).Methods: Forty patients with primary RLS who showed an index of leg movements greater than 40 during the SIT were selected for these analyses.Results: In general, Coleman's criteria for scoring PLMS were appropriate for scoring leg movements during the SIT. However, a substantial number of leg movements lasted between 5 and 10 s, exceeding Coleman's maximum duration criterion. The other criteria used to score PLMS (i.e. movements separated by 4-90 s and occurring in series of four consecutive movements) allowed detection of more than 90% of all leg movements recorded during the SIT. The distribution of inter-movement intervals (IMI) suggests that a great majority of leg movements recorded during the SIT are periodic, with a modal value of IMI between 11-12 s.Conclusion: Considering that leg movements recorded during the SIT last longer than those occurring during sleep, we recommend using a duration criterion of 0.5-10 s for scoring the former. We also recommend using the same periodicity criteria for the SIT as those used for scoring PLMS.

Journal Article↗
PubMed2001

Daytime sleepiness and EEG spectral analysis in apneic patients before and after treatment with continuous positive airway pressure.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent apneas during sleep, resulting in repetitive hypoxemic episodes and interruptions of the normal sleep pattern. A previous study showed EEG slowing (ie, a higher ratio of delta + theta frequencies to alpha + beta frequencies on EEG) during rapid eye movement (REM) sleep and wakefulness in untreated OSAS patients. STUDY AND OBJECTIVES: To determine whether EEG slowing is reversible with continuous positive air pressure (CPAP) treatment and to verify whether the persistence of excessive daytime sleepiness (EDS) is correlated with residual slowing of the EEG. PATIENTS: Ten healthy subjects (9 men and 1 woman) and 14 patients with moderate-to-severe OSAS (13 men and 1 woman) were studied before and after 6 months of treatment with CPAP. RESULTS: Untreated OSAS patients showed EEG slowing in frontal and central cortical regions during both wakefulness and during REM sleep compared to healthy control subjects. This EEG slowing was found to be independent of time spent with arterial oxygen saturation < 90%, severity of OSAS, or mean sleep latency as determined by the multiple sleep latency test. CPAP treatment was found to correct the EEG slowing for both REM sleep and wakefulness. Daytime sleepiness also greatly improved with treatment, but some degree of somnolence remained. CONCLUSION: CPAP treatment was found to correct the EEG slowing that was observed in untreated OSAS patients. Persistent EDS may be related to persistent obesity after CPAP treatment.

Adult↗
PubMed2000

Arm restlessness in patients with restless legs syndrome.

Restless legs syndrome (RLS) is a neurologic disorder characterized principally by leg paresthesia and motor restlessness. Several clinical reports indicated that many patients with RLS also have arm paresthesia and restlessness. In the present study, the incidence of arm restlessness was assessed by questionnaire in 230 patients diagnosed with idiopathic RLS. Arm restlessness was reported by 48.7% of the patients. Patients with and without arm restlessness were compared with regard to clinical and polysomnographic parameters. No between-group differences were found for age at onset of RLS, duration of illness, gender, presence of a family history of RLS, sleep latency, total sleep time, sleep efficiency, and periodic leg movements index during sleep. However, arm restlessness was more frequent in patients with severe RLS. Interestingly, the polysomnographic data failed to differentiate the patients with arm restlessness from those without arm restlessness, except for sleep efficiency, which tended to be lower in patients with arm restlessness. In conclusion, the results of the present study are in agreement with clinical observations that a large proportion of patients with RLS have arm restlessness.

Adult↗
PubMed2000

Sleep arousal response to experimental thermal stimulation during sleep in human subjects free of pain and sleep problems.

Although the interaction between sleep and pain is generating considerable interest (NIH Technology Assessment Panel, 1996), it is still unknown if chronic pain is the cause or effect of poor sleep. To further this understanding, subjects free of pain and sleep problems need to be studied in order to assess their response to pain during sleep, defined as a behavioral and a physiological state in which sensory processing is altered. (For example, while auditory perception remains active, other sensory inputs are facilitated, attenuated, or suppressed (Velluti, 199746 degrees C) was statistically greater in the lighter sleep stage 2 (48.3%) than in the deeper stages 3&4 (27.9%). A nocifensive behavioral-motor response was associated with only 2.5% of the 351 heat pain stimuli. Two other markers of sleep quality-sleep stage shift and awakening-were not influenced by the thermal stimuli. None of the subjects demonstrated any burns in the morning following the thermal stimulations applied during sleep. We conclude that the processing of nociceptive inputs is attenuated across sleep stages.

Adult↗
PubMed1999

Novel Polymeric Carbonylhaloruthenium(I) Polyanions: Rational Design and Self-Reorganization in the Presence of CO(2) and H(2)O.

We just need to mix [Ru(CO)(3)Cl(2)(thf)] with methanolic NEt(4)OH-nature will do the rest: The unsaturated fragments thus generated spontaneously polymerize with production of CO(2) and H(2)O, which combine to give the carbonate ligands of the ruthena-crown species obtained (shown schematically). The carbonate groups, rarely seen in ruthenium carbonyl complexes, are responsible for the observed annulation, and hold consecutive Ru dimers together by acting as bridging and doubly chelating ligands.

Journal Article↗
PubMed1999

A triple beta-spiral in the adenovirus fibre shaft reveals a new structural motif for a fibrous protein.

Human adenoviruses are responsible for respiratory, gastroenteric and ocular infections and can serve as gene therapy vectors. They form icosahedral particles with 240 copies of the trimeric hexon protein arranged on the planes and a penton complex at each of the twelve vertices. The penton consists of a pentameric base, implicated in virus internalization, and a protruding trimeric fibre, responsible for receptor attachment. The fibres are homo-trimeric proteins containing an amino-terminal penton base attachment domain, a long, thin central shaft and a carboxy-terminal cell attachment or head domain. The shaft domain contains a repeating sequence motif with an invariant glycine or proline and a conserved pattern of hydrophobic residues. Here we describe the crystal structure at 2.4 A resolution of a recombinant protein containing the four distal repeats of the adenovirus type 2 fibre shaft plus the receptor-binding head domain. The structure reveals a novel triple beta-spiral fibrous fold for the shaft. Implications for folding of fibrous proteins (misfolding of shaft peptides leads to amyloid-like fibrils) and for the design of a new class of artificial, silk-like fibrous materials are discussed.

Adenoviruses, Human↗
PubMed1999

EEG and cardiac activation during periodic leg movements in sleep: support for a hierarchy of arousal responses.

OBJECTIVE: To investigate other physiologic changes that occur with periodic leg movements during sleep (PLMS) that might be considered to be more sensitive indices of sleep fragmentation. BACKGROUND: Although PLMS are associated with recurrent microarousals (MA), the frequency of PLMS with MA does not correlate with objective daytime sleepiness. It is postulated that the lack of correlation results from the low sensitivity of the standard criteria used to score MA. METHODS: Ten drug-free patients with a polygraphic and clinical diagnosis of restless legs syndrome (RLS) and PLMS were examined. The EEG correlates of PLMS were analyzed by visual scoring and spectral analysis during PLMS that ended in a visible microarousal (PLMS with MA) or not (PLMS without MA). The R-R interval in the EKG signal was also examined. RESULTS: A total of 34% of PLMS were associated with MA lasting >3 seconds, and 3% of PLMS were associated with MA lasting <3 seconds. Although PLMS with MA were associated with an increase in alpha activity, for PLMS without MA a significant increase in delta and theta activity was present. Both types of PLMS induced a shortening of the R-R interval; this was particularly more marked for PLMS with MA. CONCLUSIONS: First, visual scoring of MA that include a duration of less than 3 seconds has little effect on the detection of PLMS with MA. Second, EEG activation and tachycardia are present during both types of PLMS. Third, a hierarchy in the arousal response is present-going from autonomic activation to bursts of delta activity to alpha activity to a full awakening.

Analysis of Variance↗
PubMed1999

The influence of sex, age and sleep/wake state on characteristics of periodic leg movements in restless legs syndrome patients.

Restless legs syndrome (RLS) patients experience periodic stereotyped leg movements while awake and during sleep. The aim of the present study was to measure the effects of sex, age and the sleep/wake state on several characteristics (frequency, duration and periodicity) of these periodic leg movements (PLM). One hundred unrelated patients diagnosed with primary RLS were studied. During wakefulness, frequency of PLM increased and the mean inter-movement interval decreased with advancing age. The modal value of inter-movement interval distribution was also altered suggesting that aging influences rhythm-generation mechanisms. Sleep/wake states had a profound effect on leg movement characteristics. Movements of longer duration were seen during wakefulness, while REM sleep was characterized by the shorter duration and the lowest frequency of PLM, due most likely to the inhibition of spinal motoneurons that prevails in REM sleep. States of vigilance also modulated the periodicity of PLM. Intervals were shorter during wakefulness and increased progressively from stage 1 to stage 2 sleep, and to slow wave sleep (SWS). During REM, the duration of sleep intervals returned to values obtained in stage 1 sleep; these two stages sharing similar patterns of EEG activity. These results indicate that a single state dependent mechanism may be responsible for the periodicity of PLM noted both during sleep and wakefulness.

Adult↗
PubMed1999

Differential effects of morphine on pain and temperature perception in human volunteers.

Electrophysiological and behavioral evidence suggests that morphine may have a differential effect on nociceptive and thermal pathways. In this study, we explored the perceptual consequences of these differential actions by examining the effect of a low morphine dose (0.08 mg/kg) on pain and temperature sensations arising from cutaneous thermal stimuli. In a double-blind placebo-controled study, we compared the perceived temperature intensity and perceived pain intensity and unpleasantness of noxious and innocuous heat and cold applied to the face of human subjects, with and without low doses of systemic morphine. The results showed that morphine modified pain-related sensations. In contrast, perceived thermal intensity of both noxious and innocuous heat or cold stimuli was unchanged by low-dose morphine administration. These findings suggest that low doses of morphine have a differential effect on pain and temperature sensations arising from the same stimulus, and thus that these sensations could be subserved by different neuronal populations. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗
PubMed1998

Immobilization tests and periodic leg movements in sleep for the diagnosis of restless leg syndrome.

Patients with restless leg syndrome (RLS) complain of motor restlessness, usually occurring while they rest in the evening. Two immobilization tests have been described to assess leg restlessness in these patients. In the first test, the patient sits in bed with his or her legs outstretched while electromyograms are recorded from right and left anterior tibialis muscles for an hour (Suggested Immobilization Test [SIT]); in the second test, the legs are immobilized in a stretcher (Forced Immobilization Test [FIT]). In the current study, the SIT and the FIT were compared in patients with RLS and normal control subjects matched for age and sex. More leg movements were seen in patients than in controls during immobilization tests, especially the SIT. These movements were periodic, occurring at a frequency of approximately one every 12 seconds. The SIT (index > 40) was found to discriminate between RLS and control subjects better than the FIT (index > 25). Patients were also recorded during two consecutive nights to measure periodic leg movements in sleep (PLMS). A SIT index greater than 40 and a PLMS index greater than 11 (highest PLMS index of 2 consecutive nights) were found to discriminate patients with RLS from control subjects with similar power. With each of these two measures, the clinical diagnosis was correctly predicted in 81% of patients and 81% of the control subjects. The SIT has several advantages over the measure of the PLMS index; it does not require an all-night polygraphic recording and can be administered several times a day to measure circadian fluctuation of motor restlessness.

Adult↗
PubMed1998

Spectral analysis of wakefulness and REM sleep EEG in patients with sleep apnoea syndrome.

Neuropsychological investigations of patients with obstructive sleep apnoea syndrome (OSAS) have shown impairments in such basic functions as memory, attention and executive control. Since executive functions are known to be dependent on the integrity of the frontal lobe, it was hypothesized that OSAS may be associated with hypoxaemic frontal lobe dysfunction. To test this hypothesis, 21 apnoeic patients and 10 normal controls were studied with quantitative electroencephalographic (EEG) methods during rapid eye movement (REM) sleep, when most apnoeic events occur and during wakefulness. In apnoeic patients, EEG slowing in REM sleep was observed over frontal, central and parietal regions, while EEG slowing during wakefulness was observed over all cortical regions examined. A positive correlation was found between EEG slowing during wakefulness and oxygen desaturation during the night. Contrary to the hypothesis, these electroencephalographic changes were not localized only to the frontal region. This result may explain the wide range of neuropsychological deficits noted in patients with obstructive sleep apnoea syndrome, in addition to their poor performance in tasks of executive functioning.

Adult↗
PubMed1997

Clinical, polysomnographic, and genetic characteristics of restless legs syndrome: a study of 133 patients diagnosed with new standard criteria.

One hundred thirty-three cases of restless legs syndrome (RLS), diagnosed with criteria recently formulated by an international study group, were studied by questionnaire and with all-night polysomnographic recordings. Results show that RLS starts at a mean age of 27.2 years and before age 20 in 38.3% of patients. Symptoms often appear in one leg only and also involve upper limbs in about half of all cases. Most patients (94%) report sleep-onset insomnia or numerous nocturnal awakenings due to RLS symptoms. A strong relationship was found between these complaints and polysomnographic findings; increasing sleep latency and number of awakenings and decreasing sleep efficiency were associated with worsening symptoms. Periodic leg movements in sleep (index > 5 movements/h sleep) were found in 80.2% of patients. This study shows that this percentage is increased when 2 recording nights are considered (most severe score). Eighty patients of 127 (63%) reported the presence of RLS in at least one of their first-degree relatives. In these families, 221 of 568 first-degree relatives (39%) were reported by the patients to be affected with RLS.

Adult↗