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Biomedical subjects

E Delpont

Publications and source records attributed to E Delpont.

14 recordsLinked to original sources
PubMed1994

[Lambert-Eaton syndrome without calcium channel autoantibodies].

Two cases of Lambert-Eaton syndrome are reported, one associated with a small cell lung carcinoma, the other without any etiology at the time of the study. None of these cases showed significant titers of calcium channel autoantibodies. The heterogeneity of the Lambert-Eaton syndrome and the responsibility of the autoantibodies detected by immunoprecipitation of the voltage-gated calcium channel in the occurrence of the neuromuscular block are discussed.

Adult↗
PubMed1991

Visual evoked potentials: differences related to physical activity.

Visually evoked potentials to patterned stimuli were recorded from tennis players, rowers and non-athlete control subjects. Each group consisted of 12 males and 12 females of similar age. Tennis players showed shorter P100 latencies compared to those of control subjects and rowers. This difference exists, in the same range, both in the male and in the females. The analysis of covariance and multiple linear regressions show that these shorter latencies cannot be explained by head circumference or by height. The hypothesis of a relationship between these shorter latencies and the specific qualities of racket players is suggested. A second experiment with squash players seems to confirm these first results.

Adolescent↗
PubMed1990

Quantitative EEG abnormalities and asymmetries in patients with intracranial tumors.

Quantified EEG data of 50 patients with intracranial tumors (T) were compared to the data profile of 60 normal adults (N), using univariate and multivariate statistical analyses. EEGs were recorded from 16 derivations. Twelve spectral parameters were computed from each lead and used for statistical comparisons. The number of significant deviations (P less than 0.05) among univariate features did not separate the T subjects from the N subjects with an acceptable sensitivity. A significant improvement was achieved by using multivariate features and particularly asymmetry multivariate features which detected 49/50 of the T subjects. The proportion of correctly lateralized tumors was 43/48.

Adult↗
PubMed1990

[Prolonged confusion syndrome in the course of cyclosporine treatment: a state of confusion?].

Cyclosporine is a potent immunosuppressant that is more and more widely used, particularly after organ transplantations. Many neurological side effects, including convulsions, that could be related to this drug, have been previously observed, most often with high blood concentrations. We report, for the first time, a case of prolonged confusion where a non convulsive status epilepticus may be discussed. It occurred in a 64-year-old woman, 17 days after a liver transplantation. The whole blood cyclosporine value was 230 micrograms/l (normal range: 100-200 micrograms/l) at the beginning of the status epilepticus. The cyclosporine imputability and the part of other factors that could have facilite are discussed.

Chronic Disease↗
PubMed1990

[A case of deep sleep myoclonus in newborn infants].

The authors report on the case of a newborn infant without pathological history suffering from severe and lasting myoclonus occurring during deep sleep and associated with normal electroencephalogram. Deep sleep myoclonus is a benign syndrome which disappears spontaneously within a few months. The long-term prognosis is excellent, but the etiology remains unknown.

Humans↗
PubMed1989

[EEG recorded after effort in triathletes. Influence of prior inhalation of hyperbaric oxygen].

Quantitative EEG was recorded during 3 sessions, once a week, in 10 high-level amateur triathletes, who regularly competed in triathlon. At each session, the EEG was recorded 15 min after a submaximal exercise test. During the second session, the exercise test came immediately after 30 min of hyperbaric oxygenation (100% oxygen at 2 atmosphere absolute pressure). The others conditions of the EEG recording were the same for the 3 sessions. The purpose of the work was to study the variations of the EEG power spectrum (from 1 to 20 Hz) which occurred between the 3 sessions. Descriptive analysis of the results show, after hyperbaric oxygenation, a diffuse increase of absolute power for several frequencies in the theta, alpha and beta bands.

Administration, Inhalation↗
PubMed1988

[Electrophysiological study of a family of subjects presenting primary hypertrophic neuritis].

Primary hypertrophic neuritis (hereditary motor and sensory neuropathy types I and III) can easily be characterized in affected families by nerve conduction measurement. Such a study is reported in a family with two affected subjects from two successive generations, a man and one of his daughters (type I). Nerve conduction velocities (NCV) were dramatically low (down to 10 m/sec) in three other subjects from the second generation without any obvious clinical symptom. These cases show again the lack of correlation between electrophysiological data and clinical features in these affections. They emphasize the usefulness of electrophysiological diagnosis among subjects without any obvious clinical sign.

Adolescent↗
PubMed1987

[Statistical EEG detection of subjects with intracranial tumors. Study of a sample of 40 quantified recordings].

Spectral analysis of 16 channel EEG recordings was applied to 40 normal subjects (N) and 40 patients with supratentorial intracranial tumor (T). A set of 22 spectral parameters was computed from each lead. This study tries to evaluate if univariate and multivariate scoring techniques of quantified EEG data can achieve good separation of the two groups. A reference profile of data is derived from the standardized data of the group N. The 40 patients as well as the 40 normal subjects are compared to the reference data profile. Scorings from 264 univariate features do not separate the two groups. Scorings from a smaller number of multivariate features proved to be more powerful and distinguished 90% of patients. Badly classified subjects are discussed.

Adult↗
PubMed1986

[3H]nitrendipine receptors as markers of a class of putative voltage-sensitive Ca2+ channels in normal human skeletal muscle and in muscle from Duchenne muscular dystrophy patients.

Properties of nitrendipine receptors have been analyzed in skeletal muscle from normal young boys and boys with Duchenne muscular dystrophy (DMD). The dissociation constant (Kd) of the complex formed by nitrendipine with its specific receptors was 0.5 +/- 0.1 nM in dystrophic muscle and 0.4 +/- 0.1 nM in normal muscle. Maximum binding capacities Bmax were 403 +/- 80 and 460 +/- 60 fmol/mg protein in DMD and normal muscle, respectively. These results suggest that nitrendipine binding sites on nitrendipine-sensitive Ca2+ channel binding sites are not altered in Duchenne muscular dystrophy.

Calcium↗
PubMed1986

[A case of myopathy with carnitine deficiency].

Clinical and biological criteria of myopathies associated with carnitine deficiency allow to distinguish a muscular and a systemic form of the condition. In this report, the results of clinical, pathological and electrophysiological data obtained from a patient with carnitine deficiency-linked myopathy are described. The patient was a 23-year-old girl who was previously known to suffer from muscle weakness when suddenly acidosis associated with a severe drop in plasma carnitine appeared. In addition there were hypermetabolic symptoms similar to those described in Luft's syndrome. Biopsy from the quadriceps femoris muscle before treatment revealed that all type I fibers were either hypotrophic or atrophic. They showed lipid overloading manifested by triglyceride droplets adjacent to the mitochondrial membrane. Furthermore, the level of soluble muscle carnitine was 83 p. 100 less than in controls and membrane linked muscle carnitine was also 73.5 p. 100 less than in controls. The patient rapidly recovered after the initiation of daily treatment with 4.40 g carnitine chlorhydrate associated with 50 g Lipogram 20. Nine months later, lipid overloading completely disappeared and the level of plasma carnitine returned to near normal whereas the level of both soluble and linked carnitine remained very low. To provide more information on the origin of the myopathy (myogenic, neurogenic or humoral) we carried out an electrophysiological investigation of cultured skeletal muscle cells from the patient and from biopsies of patients not known to be suffering from myopathy. The electrophysiological data showed that the patient myotubes were less polarized than myotubes from control patients. Furthermore, the amplitude of the action potential was smaller than the amplitude of the action potential measured in control cells. Daily addition of 50 microM carnitine chlorhydrate to the cultured myotubes induced a recovery of the action potential amplitude. Taken together these results indicate that the carnitine deficiency reported here was probably of systemic origin in addition to a myogenic component. Muscle deficiency could be either linked to an alteration in the carnitine pathway or to overconsumption of carnitine by muscle. This latter point is discussed.

Action Potentials↗
PubMed1983

[3H]nitrendipine receptors in skeletal muscle.

The richest source of receptors for the organic calcium channel blocker [3H]nitrendipine in muscle is the transverse tubule membrane. The tubular membrane preparation binds [3H]nitrendipine with a high affinity and has a very high number of [3H]nitrendipine binding sites. For example, for the transverse tubule membrane preparation from rabbit muscle, the dissociation constant of the nitrendipine-receptor complex is 1.8 +/- 0.3 nM and the maximum binding capacity Bmax = 50 +/- 6 pmol/mg of protein. Similar results have been found with a membrane preparation from frog muscle. The dissociation constant found at equilibrium is near that determined from the ratio of rate constants for association (kappa 1) and dissociation (kappa-1). Binding of [3H] nitrendipine is pH-dependent and reveals the presence of an essential ionizable group with a pK of 5.4 on the nitrendipine receptor. The binding is destroyed by proteases showing that the receptor is a protein. Three different classes of Ca2+ channel blockers inhibit [3H]nitrendipine to its specific site. (i) The dihydropyridine analogs of nitrendipine which are competitive inhibitors of [3H]nitrendipine. These molecules form tight complexes with the nitrendipine receptor with dissociation constants between 1.4 and 4.0 nM. (ii) Other antiarrhythmic molecules like verapamil, amiodarone, bepridil, and F13004 which are noncompetitive inhibitors of [3H]nitrendipine binding with dissociation constants between 0.2 and 1 microM. (iii) Divalent cations like Ni2+, Co2+, Mn2+, or Ca2+ which are noncompetitive inhibitors of [3H]nitrendipine binding with the following rank order of potency: Ni+ (K0.5 = 1.8 mM) greater than Co2+ (K0.5 = 2.7 mM) greater than Mn2+ (K0.5 = 4.8 mM) greater than Ca2+ (K0.5 = 65 mM).

Animals↗
PubMed1983

Ontogenic appearance of Na+ channels characterized as high affinity binding sites for tetrodotoxin during development of the rat nervous and skeletal muscle systems.

The appearance of the voltage-dependent Na+ channel during the fetal and post-natal development of rat brain, cerebellum and skeletal muscle has been followed using a highly radiolabelled derivative of tetrodotoxin. The number of Na+ channels is low at the fetal stage and increases drastically during post-natal development. The time-course of this increase is different in brain, cerebellum and skeletal muscle. Changes in affinity of the Na+ channel for tetrodotoxin occur during brain and cerebellum development. The results are discussed in relation with the maturation of the three types of excitable tissues.

Aging↗
PubMedDate not supplied

Long latency event-related potentials (P300) in gifted children.

In children, P3 latency decreases with increasing age. This decrease could be linked with the maturation of cognitive processes. According to this hypothesis, event-related potentials P3 were recording in gifted children to research an electrophysiological correlation with the mental precocity. Auditory long latency event-related potentials were recorded in 10 gifted children (IQs over 140) and 23 control subjects. The part of variance related to age was extracted by comparing deviations from regression line as a function of age. Stimulus-evoked N1 component latency was not statistically different in the two populations. Event-related P3 component latency was significantly shorter in the gifted children at Cz (P < 0.05). Inter-peak interval N1-P3 was significantly shorter at all three recording sites (P < 0.01 at Fz and CZ, P < 0.02 at Pz). These results suggest a relationship between the P3 component and cognitive ability in children.

Acoustic Stimulation↗