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Biomedical subjects

C Bonnet

Publications and source records attributed to C Bonnet.

At least 55 records · Page 3Linked to original sources
PubMed1999

Response times to Ehrenstein illusions of varying subjective magnitude: complementarity of psychophysical measures.

The following experiments investigate the effects of contrast polarity, inducer spacing, and inducer type on three dependent variables measuring the perception of an illusory surface in Ehrenstein figures: subjective magnitude, response time, and frequency of perception. It was found that response time generally decreased when the other two behavioral indicators increased. However, it was also shown that subjective magnitude provided more discriminating measures of relatively strong illusory percepts, whereas frequency of perception and response time provided more discriminating measures of relatively weak illusory percepts. The findings generally confirm earlier work on the effect of inducer spacing and contrast polarity on the perceived strength of brightness illusions, and in particular reveal the complementarity of subjective magnitude, response time, and frequency of perception as critical measures of configurational effects in the perceptual processing of these phenomena.

Adult↗
PubMed1999

Long-term cyclosporin continuation rates in rheumatoid arthritis patients.

OBJECTIVE: To evaluate the continuation rate of cyclosporin therapy in rheumatoid arthritis patients followed for at least three years. METHODS: Retrospective medical chart review of rheumatoid arthritis patients on cyclosporin. Treatment efficacy was assessed based on a visual analog scale pain score, Ritchie's articular index, and Lee's functional index. Nonparametric Kaplan-Meier survival curves were used to evaluate continuation rates. RESULTS: 24 cyclosporin-treated patients with a mean age of 58 years and a mean disease duration of ten years were included in the study; 87% had received three second-line drugs prior to cyclosporin. Mean cyclosporin treatment duration was 28 months (range, 1-103 months). Overall cyclosporin continuation rates were 75% after four months and 50% after 36 months. Toxicity and inefficacy caused 33% and 13% of cyclosporin discontinuations, respectively. CONCLUSION: The continuation rate of cyclosporin was satisfactory and similar to that reported for other second-line drugs.

Adult↗
PubMed1999

Longitudinal determination of antiphospholipid antibodies in lupus patients without previous manifestations of antiphospholipid syndrome. A prospective study.

OBJECTIVE: To investigate whether serial anticardiolipin determination contributes to the clinical management of patients with systemic lupus erythematosus (SLE) with no previous sign of the antiphospholipid syndrome (APS). METHODS: In 90 patients with SLE with no previous clinical manifestations of the APS, repeated clinical evaluations were performed, and serial blood samples (obtained over a 30 month period, range 13-53 mo) were screened for antiphospholipid antibodies (aPL). Anticardiolipin antibodies (aCL) were detected using an ELISA and considered positive if the result was >25 GPL on 2 separate occasions. Patients were not required to be on a specific treatment regimen during the study. RESULTS: Thirty-four patients (37%) had at least one positive ELISA and 11 (11/90, 12%) 2 positive ELISA for IgG aCL during the study. Lupus anticoagulant (LAC) was found in 16 patients, and a false positive VDRL in 5. At study completion, the total number of clinical or laboratory events associated with APS was 30. In univariate analysis, aCL was significantly associated only with LAC (p<0.012). Presence of aCL also correlated with hemoglobin level, anti-DNA antibody, leukocyte count, and the SLE Disease Activity Index (SLEDAI). LAC and aCL were significantly associated with each other (OR 5.17; 95% CI 1.5-17.7), but LAC had a better positive predictive value than aCL for arterial thrombosis and neurological events. CONCLUSION: Among our patients with SLE without previous clinical manifestations of APS, positive aCL did not predict the occurrence of APS within the next 3 years, but was statistically related to the clinical disease activity (SLEDAI).

Adolescent↗
PubMed1998

[Male osteoporosis].

AN UPCOMING PUBLIC HEALTH PROBLEM: There has been a considerable focus on osteoporosis in men recently. Bone mass is high in men who have larger bones than women. The frequency of fractures is also higher due to post-trauma lesions. Femoral neck fractures have also increased over the last few years although the F/M ratio remains about 2.8. Overall, there is a trend towards an increased incidence of masculine osteoporosis (and vertebral fractures) due to population aging. FAVORING FACTORS IN MEN: The most important factors are hypoandrogenism, hypoestrogenism (pre or post-puberty), the alcohol-smoking association, malnutrition, lack of sun exposure and chronic liver disease. Other causes of osteoporosis (hyperthyroidism, Cushing's disease, hemochromatosis, gastrectomy, inflammatory rheumatic disease, tubulopathy, hypercalciuria and iatrogenic causes) should also be taken into consideration. PRETHERAPY WORK-UP: All the different possible etiologies should be investigated. Therapeutic protocols should provide hormone replacement when required, withdrawal of causal drugs, better nutrition and reduced alcohol and tobacco use.

Bone Density↗
PubMed1998

In vivo voltammetric detection of rat brain lactate with carbon fiber microelectrodes coated with lactate oxidase.

To allow rat brain lactate measurement in vivo, a specific sensor based on a carbon fiber (phi = 30 microns) microelectrode coated with lactate oxidase was prepared. Combined with the differential normal pulse voltammetry measurement method, such a sensor, with a sensitivity of 9.15 +/- 0.91 mA.M-1.cm-2, provided a lactate linear response in concentrations ranging from 0.1 to 2.0 mM. The measurements performed appeared to be essentially insensitive to usual interference caused by the electroactive compounds present in the brain (ascorbic acid and peptides). In vivo detection performed in the cortex of the anesthetized rat led to the determination of a lactate concentration of 0.41 +/- 0.02 mM. Moreover, to validate the results obtained in vivo, an ex vivo determination of the lactate level was also performed in samples of brain tissue, plasma, and cerebrospinal fluid, using both voltammetry and a clinical analyzer with colorimetric-based detection. A good correlation was observed between the sets of data established by both methods.

Animals↗
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

Learning difficulties of diabetic patients: a survey of educators.

This study was designed to shed light on the learning difficulties of diabetic patients. An open-ended questionnaire was sent to 85 health care professionals working in the field of diabetes and nutrition who had been trained in patient education techniques. They were asked to describe the skills that were the easiest to teach patients and those that patients mastered the best, as well as the skills they found hardest to teach patients, those that patients mastered the least and those that gave rise to errors persisting after the patients education was completed. On the whole, the results showed that the educators found it easy to teach techniques: patients mastered procedures well and made few mistakes. In contrast, diabetic patients seem to have problems learning skills, such as insulin dose adjustment, that require complex problem-solving (involving multiple variables). Based on these findings, the authors discuss the notions of learning complexity and the time needed for successful patient education.

Attitude of Health Personnel↗
PubMed1998

Expression of growth factors and their receptors in the postnatal rat cochlea.

RT-PCR was used to assay for growth factors and receptors from seven different protein families in cochlea tissues of the juvenile rat. There was a broad representation of the growth factor families in all the cochlea tissues examined, though the organ of Corti and stria vascularis expressed a greater variety than the spiral ganglion. This broad expression suggests that a variety of known growth factors play significant roles in the development, maintenance, and repair of the inner ear. The results of this survey serve as a basis for the design of future in vitro experiments that will address the ability of growth factors to protect hair cells from damage and to evoke a repair-regeneration response by injured hair cells.

Animals↗
PubMed1998

Is there an optimal time to administer methotrexate in the treatment of rheumatoid arthritis?

OBJECTIVE: To determine the optimal time to administer methotrexate (MTX) in rheumatoid arthritis (RA). METHODS: In a crossover study 23 patients were administered MTX intramuscularly at either 10 AM or 6 PM. A 2 week interval separated the 2 injections. MTX concentrations were measured using a fluorescence polarization immunoassay. Pharmacokinetic variables were estimated using a Bayesian approach. The morning and evening schedules were compared using analysis of variance to determine the optimal time of injection. RESULTS: No statistical difference was found in the pharmacokinetics of MTX according to hour of injection. A difference in the creatinine clearance, however, was observed in the samples obtained at noon and 8 PM, but clearance of MTX was unchanged. CONCLUSION: Pharmacokinetic variables suggest that MTX can be administered either in the morning (10 AM) or evening (6 PM) in the treatment of RA.

Adult↗
PubMed1997

Influence of a 1 h immobilization stress on sleep states and corticotropin-like intermediate lobe peptide (CLIP or ACTH18-39, Ph-ACTH18-39) brain contents in the rat.

A 1 h immobilization stress (IS) was imposed to rats at the beginning of the dark period, i.e., when the animals start to be active. The IS was accompanied by an intense polygraphic waking and followed, over 12 h of the dark period, by a significant rebound of slow-wave sleep (SWS, +17%) and paradoxical sleep (PS, +57%). In order to estimate the IS-related changes in the endogenous concentrations of corticotropin-like intermediate lobe peptide (CLIP, ACTH18-39) and related compounds, a specific radioimmunoassay (RIA) was used. Assays performed in cerebral biopsies taken from arcuate (AN) and raphe dorsalis (nRD) nuclei led to the obtention of 2 main immunoreactive peaks, corresponding to CLIP and its phosphorylated form Ph-CLIP. Just after end of the IS and within the nRD. Ph-CLIP immunoreactivity increased by about 95%. Four hours later, i.e., when PS rebound was maximal, a 37% increase in Ph-CLIP immunoreactivity was measured in the AN. These observations have never been described before. In the blood, at the end of the restraint, CLIP/ACTH1-39 total immunoreactivity was increased by 330%. It returned to baseline level 4 h later. Blood concentration of corticosterone was also increased by 56% at the end of the IS and was close to baseline level 4 h later. Data reported here indicate that the IS first triggers an increase in Ph-CLIP within the nRD. Since the nRD contains sleep permissive components, this increase might be determinant for the SWS and PS rebound induction. The changes observed in the blood as regards CLIP/ACTH1-39 total immunoreactivity and corticosterone concentration testify to the efficacy of the IS and are part of the conventional picture accompanying such a situation. Finally, the increase in Ph-CLIP, occurring in the AN 4 h after the end of the restraint, might be part of the restorative processes necessary to compensate the stress overshoot.

Adrenocorticotropic Hormone↗
PubMed1997

Ultrastructural relationships of the pro-opiomelanocortin axons with the serotoninergic neurons in the dorsal raphe nucleus of the rat.

The relationships of the corticotropin-like intermediate lobe peptide (CLIP)/ACTH-immunoreactive axons with the serotoninergic and non-serotoninergic neurons in the dorsal raphe nucleus of the rat were examined by means of a double label immunocytochemical method. It is suggested that the rare contacts established by the CLIP/ACTH-immunoreactive fibers with serotoninergic neurons (cell bodies and dendrites) are not under a synaptic from. In contrast, the contacts with non-serotoninergic neurons were predominantly formed with dendrites and showed a substantial number of synapses.

Adrenocorticotropic Hormone↗
PubMed1997

Hemispheric asymmetries of visual evoked potentials in relation to spatial frequency, handedness and familial left-handedness.

The effects of handedness and of familial left-handedness on the asymmetry of the cerebral hemispheres were investigated by means of visual evoked potentials. Square gratings of different spatial frequencies were presented, at 1 Hz in ON-OFF mode to 60 subjects: 30 right-handers and 30 left-handers, 15 with familial handedness and 15 without in each group. The results show that the patterns of hemispheric asymmetry differ in right- and left-handers. They also show that in left-handers these patterns depend on the presence or absence of familial left-handedness, whereas in right-handers the role of this genetic factor is less evident.

Adolescent↗
PubMed1997

Supplementation with wine phenolic compounds increases the antioxidant capacity of plasma and vitamin E of low-density lipoprotein without changing the lipoprotein Cu(2+)-oxidizability: possible explanation by phenolic location.

OBJECTIVES: To evaluate the effect of the red wine phenolic compound (RWPC) dietary supplementation without alcohol interference on: (1) some of the biochemical characteristics of LDL, (2) the oxidative susceptibility of LDL and (3) the antioxidant capacity of total plasma (Pl-AOC). In order to account for discrepancies between the three series of data, the in vitro stability of the association of phenolic compounds and LDL was tested. DESIGN: An intervention study with 20 volunteers. Each served as his own control. Cu(2+)-oxidizability of LDL and Pl-AOC were tested on blood samples before and after dietary supplementation. Cu(2+)-oxidizability of LDL was also tested by co-incubation in the presence of RWPC or phenolic acids with or without extensive dialysis. SETTING: The Laboratory of Lipid Biochemistry and Biology, School of Medicine, and the Laboratory of Metabolic Diseases, Lapeyronie Hospital, University of Montpellier, France. SUBJECTS: Healthy males, nonsmokers and moderate drinkers, submitted to a dietary regimen deprived of vitamin E and C for a period of 10 d before supplementation. They also abstained from alcohol, wine, fruit juices, coffee, tea and cola beverages during this period. INTERVENTION: Six 0.33 g capsules/d (namely two capsules at each meal) of a preparation of red wine phenolic compounds in a dry powder form were given to the volunteers over a period of two weeks. Blood samples were drawn in fasting conditions at day 0 and day 14 of the supplementation period. RESULTS: Supplementation led to: (1) in LDL, a significant increase in vitamin E content (n = 20, P = 0.01) or vitamin E/total fatty acid bis-allylic carbon number ratio (n = 20, P = 0.006) without modification in the other biochemical characteristics or Cu(2+)-oxidizability; (2) in plasma, a significant increase in the antioxidant capacity (n = 11, P = 0.01). In vitro studies showed that RWPC or sinapic, caffeic or ferulic acids incubated in the presence of LDL increased the protection of the lipoparticle against oxidation (caffeic > sinapic > ferulic). This effect, however, was totally lost after extensive dialysis. CONCLUSIONS: The enhancing effect of the RWPC supplementation on Pl-AOC may be due to a phenolic-compound action both in the aqueous phase of plasma and at the surface of lipoprotein particles. Surface location possibly explains the enhancing-sparing effect of supplementation on LDL vitamin E and the absence of effect on dialysed-LDL oxidizability.

Adult↗
PubMed1996

In vitro fermentation by human faecal bacteria of total and purified dietary fibres from brown seaweeds.

The in vitro degradation of dietary fibre from three brown seaweeds (Himanthalia elongata, Laminaria digitata and Undaria pinnatifida) was studied, using human faecal flora. Two sets of fibre were tested: (1) total algal fibres extracted from the whole algae, mainly composed of alginates, and (2) purified fibres (sulphated fucans, Na-alginates and laminarans) representative of those contained in the whole brown algae. Mannuronate, one algal component, was also investigated. Substrate disappearance and short-chain fatty acid (SCFA) production were monitored after 6, 12 and 24 h fermentation. Gas production was followed hourly during the first 9 h and then at 12 and 24 h. Sugarbeet fibre was used as a fermentation reference substrate. According to the fermentative indices used, most of each of the total algal fibres disappeared after 24 h (range 60-76%) but, unlike the reference substrate, they were not completely metabolized to SCFA (range 47-62%). Among the purified algal fibres, disappearance of laminarans was approximately 90% and metabolism to SCFA was approximately 85% in close agreement with the fermentation pattern of reference fibres. Sulphated fucans were not degraded. Na-alginates exhibited a fermentation pattern quite similar to those of the whole algal fibres with a more pronounced discrepancy between disappearance and production of SCFA: disappearance was approximately 83% but metabolism was only approximately 57%. Mannuronate was slowly fermented but its metabolism corresponded to its disappearance from the fermentative medium. Thus, the characteristic fermentation pattern of the total fibres from the three brown algae investigated was attributed to the peculiar fermentation of alginates, and mannuronate was shown not to be directly involved.

Alginates↗