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Biomedical subjects

J L Pepin

Publications and source records attributed to J L Pepin.

At least 19 recordsLinked to original sources
PubMed2003

[Prevention of dementia: is it possible?].

Development of dementia depends on genetic susceptibility and on risk factors accessible to primary prevention. Among the latter, vascular risk factors are well defined: prevention of hyperhomocysteinemia, diabetes mellitus, hypercholesterolemia, and, to some extent, of arterial hypertension could avoid the cognitive decline of dementia. Estrogen replacement therapy, antiinflammatory drugs, alcohol, vitamin E and intellectual activities seem efficacious in term of primary prevention. When dementia is present, only vitamin E, selegiline and some antiinflammatory drugs have proved efficacy compared to placebo to slow the cognitive decline. Long-term effects of cholinesterase inhibitors need to be investigated in future trials.

Aged↗
PubMed2002

Identification of quality of life concerns of patients with obstructive sleep apnoea at the time of initiation of continuous positive airway pressure: a discourse analysis.

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) is a common condition with multiple symptoms dominated by daytime somnolence. Thus many worries and concerns of patients remain hidden. Treatment by nasal continuous positive airway pressure (CPAP) can be imposing for the individual. An analysis of the freely expressed concerns of such patients is required. OBJECTIVE: To seek an in-depth analysis of how patients live with sleep apnoea by allowing them an open discourse and analysing the text of their statements. DESIGN: A trained psychologist conducted semi-directive interviews with patients attending a pulmonary rehabilitation and convalescent unit around the themes of sleep, health and treatment. An analysis of content and of discourse was carried out by textual analysis and by propositional analysis of discourse (PAD) with the aid of dedicated computer programs (Tropes, Sphinx Lexica). RESULTS: Thirty patients with severe sleep apnoea were interviewed of whom 15 were initiating treatment with CPAP. Patients spoke of abnormal fatigue (22 mentions) and somnolence (21 times). Many have problems with obesity (25 instances), snoring related problems (12). There were 30 mentions of depression with a relationship to alcohol and anti-depressives. Twenty six times the theme of nocturnal waking was raised. There were many instances of problems with CPAP (nasal mask and noise problems raised 21 times). Patients have problems with relationships and sex because of OSAS. Other concerns were loss of memory and fear of dying. CONCLUSION: In a non-directed conversation OSAS patients express concerns not revealed in the standard medical paradigm and such concerns should be addressed in assessing treatment or evaluating quality of life (QOL).

Adult↗
PubMed2001

Increased lipid peroxidation in patients with pulmonary hypertension.

Isoprostanes are chemically stable lipid peroxidation products of arachidonic acid, the quantification of which provides a novel approach to the assessment of oxidative stress in vivo. The main objective of this study was to quantify the urinary levels of isoprostaglandin F(2alpha) type III (iPF(2alpha)-III), an F(2)-isoprostane, in patients with pulmonary hypertension (PHT) in comparison with healthy controls. The secondary objective was to test whether baseline iPF(2alpha)-III levels correlate to the reversibility of pulmonary hypertension in response to inhaled NO challenge. Urinary iPF(2alpha)-III levels were measured by gas chromatography-mass spectrometry in 25 patients with PHT, 14 of whom were investigated for response to inhaled NO challenge. Urinary iPF(2alpha)-III levels in PHT patients (225 +/- 27 pmol/mmol creatinine) were 2.3 times as high as in controls (97 +/- 7 pmol/mmol creatinine, p < 0.001). The mean pulmonary arterial pressure variation and the pulmonary vascular resistance variation in response to inhaled NO were correlated to basal iPF(2alpha)-III levels. This study shows that oxidative stress is increased in patients with pulmonary hypertension. Furthermore, iPF(2alpha)-III levels inversely correlate to pulmonary vasoreactivity. These observations are consistent with the hypothesis that free radical generation is involved in PHT pathogenesis.

Adolescent↗
PubMed2001

[Dementia in Belgium: prevalence in aged patients consulting in general practice].

Early detection of dementia is an important element for the efficacy of therapies currently proposed to slow down disease progression. This detection mainly relies on general practitioners. In order to estimate the impact of dementia on health services, we have estimated from the data of the NAtional Dementia Economic Study (NADES) the prevalence rate of dementia in patients aged > or = 65 years living at home and consulting in general practice. The study population was based on the sampling of consecutive patients consulting a general practitioner, irrespective of the reason and location of the consultation. The diagnosis of dementia was based on the CAMDEX performed at home in patients presenting > or = 3 warning signs of dementia. The prevalence rate of dementia among 2.234 registered patients living at home was 14.3% (CI95: 12.6-16.0). In age groups 65-74, 75-84 and > or = 85 years, it was 7.0%, 17.5% and 18.5%, respectively, in men, and 6.1%, 15.8% and 25.2%, respectively, in women. The percentage of demented with mild, mild to moderate, moderate and severe dementia was 35.0%, 38.8%, 13.1% and 13.1%, respectively. After adjusting for the age and sex distribution of the Belgian population, the prevalence rate in patients aged > or = 65 years was estimated at 11.3%. A diagnosis of dementia had already been made by a specialist in 41.5% of patients with dementia, with figures of 19.3%, 34.3%, 41.9% and 60.9% according to the severity of disease (mild, mild to moderate, moderate, severe). The onset of first symptoms had preceded the diagnosis by an average of 1 year. Our results show a high prevalence rate of dementia in the elderly living at home consulting in general practice, and less than half of the patients had previously been diagnosed. It is possible that a systematic detection will not be performed as long as specific treatments are not made widely available.

Aged↗
PubMed2000

Projections from basal ganglia to tegmentum: a subcortical route for explaining the pathophysiology of Parkinson's disease signs?

Functional changes in the organisation of neuronal circuitries are generally used to explain parkinsonian motor symptoms and levodopa-induced dyskinesias. Based on information from histology and neurophysiological microrecordings of specific basal ganglia nuclei, the most widely accepted scheme is based on a central loop which starts in the cerebral cortex, makes multiple relays in the basal ganglia, and returns to the cerebral cortex. Transcranial magnetic stimulation studies, however, reveal no significant differences in the excitability of the motor cortex between normal subjects and patients with Parkinson's disease. Furthermore, electrophysiological and audiospinal facilitation studies indicate that the activity of reticular nuclei is altered in Parkinson's disease. It therefore appears that a circuit with the cortex as the only recipient of basal ganglia output is an oversimplification. This paper explores the relationships between various basal ganglia nuclei and proposes a subcortical pathway via which modifications in the basal ganglia may influence motor function.

Animals↗
PubMed2000

Characterization of pharyngeal resistance during sleep in a spectrum of sleep-disordered breathing.

Aims of the study were 1) to compare Hudgel's hyperbolic with Rohrer's polynomial model in describing the pressure-flow relationship, 2) to use this pressure-flow relationship to describe these resistances and to evaluate the effects of sleep stages on pharyngeal resistances, and 3) to compare these resistances to the pressure-to-flow ratio (DeltaP/V). We studied 12 patients: three with upper airway resistance syndrome (UARS), four with obstructive sleep hypopnea syndrome (OSHS), three with obstructive sleep apnea syndrome (OSAS), and two with simple snoring (SS). Transpharyngeal pressures were calculated between choanae and epiglottis. Flow was measured by use of a pneumotachometer. The pressure-flow relationship was established by using nonlinear regression and was appreciated by the Pearson's square (r(2)). Mean resistance at peak pressure (Rmax) was calculated according to the hyperbolic model during stable respiration. In 78% of the cases, the value of r(2) was greater when the hyperbolic model was used. We demonstrated that Rmax was in excellent agreement with P/V. UARS patients exhibited higher awake mean Rmax than normal subjects and other subgroups and a larger increase from wakefulness to slow-wave sleep than subjects with OSAS, OSHS, and SS. Analysis of breath-by-breath changes in Rmax was also a sensitive method to detect episodes of high resistance during sleep.

Adult↗
PubMed1999

Motor cortex inhibition is not impaired in patients with Alzheimer's disease: evidence from paired transcranial magnetic stimulation.

Motor cortex excitability was studied by transcranial magnetic stimulation (TMS) in 17 patients with Alzheimer's disease (AD). Resting and active thresholds for TMS were significantly reduced in AD patients compared to young and aged healthy subjects. The maximum amplitude of the motor response evoked by TMS was also significantly increased in AD patients. We have tested if these changes are related to a modification of the short-lasting intracortical inhibition of the motor cortex by paired conditioning-test TMS. We found no significant differences between AD patients and aged healthy subjects even if there is a slight but significant difference between aged and young normal subjects. We conclude that the modification of excitability of the motor cortex does not result from an impaired intracortical inhibition.

Adult↗
PubMed1999

Methodological issues in a cost-of-dementia study in Belgium: the NAtional Dementia Economic Study (NADES).

The NAtional Dementia Economic Study (NADES) is an on-going prospective, one-year cohort study developed in Belgium to assess the socio-economic consequences of dementia in a group of patients and their caregivers (n = 400). Comparison is made with a group of subjects with cognitive impairment and no dementia (n = 100) and a group of subjects without any cognitive impairment (n = 100). Recruitment of subjects is based on screening of warning signs of dementia by general practitioners, followed by a Cambridge Mental Disorders of the Elderly Examination (CAMDEX) performed at home. This paper presents an overview of the study protocol and the rationale for basic design options, such as the choice of study population, screening strategy, and methods used for the case validation. It also presents preliminary results on the prevalence of dementia in general practice, the sensitivity and specificity of the warning signs as a screening test of dementia, and the validity of a computerised case ascertainment algorithm based on DSM-III-R criteria.

Aged↗
PubMed1998

Cognitive executive dysfunction in patients with obstructive sleep apnea syndrome (OSAS) after CPAP treatment.

We have previously described impairments of cognitive executive functions in 17 patients with OSAS in comparison with 17 normal controls, as assessed by various frontal-lobe-related tests. In the present study, 10 of these OSAS patients treated with continuous positive airway pressure (CPAP) were reevaluated after 4-6 months of treatment. Neuropsychological tasks explored attention, short-term memory span, learning abilities, planning capacities, categorizing activities, and verbal fluency. Patients were found to have normalized most of their cognitive executive and learning disabilities, but all the short-term memory tests remained unchanged. These findings are discussed in light of the contribution of the frontal-lobe-related systems to short-term memory functions, and the eventual pathogenic role played by sleep fragmentation and nocturnal hypoxemia, which are related to the occurrence of apneic and hypopneic events. In conclusion, short-term memory impairment was persistent in OSAS patients despite CPAP treatment for 4-6 months.

Adult↗
PubMed1998

Simultaneous laboratory-based comparison of ResMed Autoset with polysomnography in the diagnosis of sleep apnoea/hypopnoea syndrome.

ResMed Autoset (AS) is a simplified diagnosis system for obstructive sleep apnoea/hypopnoea syndrome (OSAS) based on the respiratory flow/time relationship by pressure variation measured through simple nasal prongs. A multicentre prospective trial was used to compare AS and polysomnography (PSG) for diagnosing 95 patients, with suspected OSAS. Physicians gave a pretest probability of the patient having OSAS. The apnoea/hypopnoea index (AHI) was compared between the two methods of diagnosis for the whole population and for subgroups according to the pretest probability. Twenty-four patients had AHI < 15 events x h(-1) on PSG and 19 AHI 15-30, and 52 patients had AHI > or = 30. Correlation between AHI assessed by AS and PSG was r=0.87 for total sleep time (TST), p<0.0001. A Bland and Altman plot gave an agreement between the two methods of +/-40%. For a threshold of AHI > or = 15 events x h(-1) to diagnose OSAS, AS has a sensitivity of 92%, specificity of 79%, positive predictive value of 93% and negative predictive value of 76%. With a pretest probability > or = 80%, sensitivity and positive predictive value were 98 and 100% respectively. Of six false negative, four had a high pretest probability (> 80%) or Epworth score > or = 10. Using these parameters as a criterion for proceeding to PSG after a negative AS study would mean that two apnoeic patients (AHI 20 and 17 events x h(-1) by PSG) would escape detection. The Autoset is useful for the detection of obstructive sleep apnoea but with high pretest probability and a negative Autoset result polysomnography should be performed.

Adult↗
PubMed1997

Functional changes of brainstem reflexes in Parkinson's disease. Conditioning of the blink reflex R2 component by paired and index finger stimulation.

Recovery curves of the R2 component of the blink reflex have been studied in 10 control subjects and 13 parkinsonian patients both after ipsilateral paired stimulation of the supraorbital nerve and after index finger stimulation. In control subjects, both types of conditioning induced a comparable marked inhibition lasting more than 600 ms. In parkinsonian patients, inhibition was reduced after both conditionings. However, differences appeared in the magnitude of the changes: after paired stimulation, it was less significant (ANOVA and post-hoc Duncan's test: p = 0.04) than after index finger stimulation (p = 0.002). In that latter situation, the more marked reduction in inhibition is interpreted, in the light of current physiologic knowledge, by hypoactivity of the Nucleus Reticularis Giganto Cellularis (NRGC) which would make less efficient inhibitory interneurones in the trigemino-facial pathway. The results are thus compatible with the suggestion that NRGC is made indirectly less active in Parkinson's disease.

Analysis of Variance↗