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Biomedical subjects

G Serratrice

Publications and source records attributed to G Serratrice.

At least 55 records · Page 3Linked to original sources
PubMed1995

Metabolization of iron by plant cells using O-Trensox, a high-affinity abiotic iron-chelating agent.

A synthetic siderophore, O-Trensox (L), has been designed and synthesized to improve iron nutrition of plants. The affinity for iron of this ligand [pFe(III) = 29.5 and pFe(II) = 17.9] is very high compared with EDTA. In spite of its high and specific affinity for iron, O-Trensox was found to be able to prevent, and to reverse, iron chlorosis in several plant species grown in axenic conditions. It also allows the iron nutrition and growth of Acer pseudoplatanus L. cell suspensions. The rate of iron metabolization was monitored by 59Fe radioiron. Ferritins, the iron storage proteins, are shown to be the first iron-labelled proteins during iron metabolization and to be able to further dispatch the metal. Using Fe(III)-Trensox, the rate of iron incorporation into ferritin was found to be higher than when using Fe-EDTA, but slower than with Fe-citrate, the natural iron carrier in xylem. During a plant cell culture, the extracellular concentrations of iron complex and free ligand were measured; changes in their relative amounts showed that the iron complex is dissociated extracellularly and that only iron is internalized. This suggests a high affinity for iron of a putative carrier on the plasmalemma. In contrast with Fe-citrate and Fe-EDTA complexes, Fe(III)-Trensox is not photoreducible. Its ability to induce radical damage as a Fenton reagent was tested using supercoiled DNA as target molecule. Unlike Fe-citrate and Fe-EDTA, Fe(II)-Trensox and Fe(III)-Trensox were proven to be harmless even during ascorbate-driven reduction, while Fe-EDTA and Fe-citrate generate heavy damage to DNA.

Chemical Phenomena↗
PubMed1995

Levorotatory form of 5-hydroxytryptophan in Friedreich's ataxia. Results of a double-blind drug-placebo cooperative study.

OBJECTIVE: To study the effect of the levorotatory form of 5-hydroxytryptophan on the cerebellar symptoms of Friedreich's ataxia. DESIGN: Cooperative double-blind study of the levorotatory form of 5-hydroxytryptophan vs placebo. SETTING: Twelve centers in research hospitals. PATIENTS: Twenty-six patients were included; 19 completed the study (mean +/- SD age of patients, 25.9 +/- 8.1 years). Of these 19 patients, eight were treated with placebo and 11 were treated with the drug. MAIN OUTCOME MEASURES: A semiquantitative scale for kinetic and static ("postural") cerebellar functions and quantitative measurements of time in standard tests that evaluated stance, speech, writing, and drawing. RESULTS: In the active treatment group, a significant decrease of the kinetic score was observed (P = .03), indicating an improvement in coordination. CONCLUSIONS: These results demonstrated that the levorotatory form of 5-hydroxytryptophan is able to modify significantly the cerebellar symptoms in patients with Friedreich's ataxia. However, the effect is only partial and not clinically major.

5-Hydroxytryptophan↗
PubMed1995

Palmaris brevis spasm syndrome.

Palmaris brevis spasm syndrome is a rare and benign condition of localised muscular hyperactivity. In five men, the hypothenar eminence underwent spontaneous, irregular, tonic contractions of the palmaris brevis muscle. An EMG showed spontaneous high frequency discharges of normal motor units, without evidence of neuropathy or of nerve compression. This syndrome resembles other restricted muscle hyperactivity syndromes although there are some differences. Curiously, the palmaris brevis muscle is not under voluntary control. The mechanism of the syndrome could be an ephaptic transmission possibly secondary to the transient and repeated stretching of the ulnar nerve superficial branch. In one patient a root compression was the probable origin.

Adult↗
PubMed1994

Association of deletion and homoplasmic point mutation of the mitochondrial DNA in an ocular myopathy.

The mitochondrial DNA of a 41 year old patient with ocular myopathy was explored. We found a deletion of 3540 base pair in about 50% of the mitochondrial genomes associated with a homoplasmic point mutation. The mutation at nucleotide pair 7444 converts stop codon AGA into lysine codon AAA (human mitochondrial genetic code). The synergistic effect between two point mutations has already been described in mitochondrial pathology but this is the first time that an association between a deletion and a point mutation is shown.

Adult↗
PubMed1994

[Disorders of walking in elderly subjects: towards new concepts].

While gait disorders directly related to a muscular, skeletal neurological defect are easily recognized, others, which we address here, appear to result from some unknown and mysterious mechanism. Gait disorders in elderly patients cannot be conceived as a simple impairment in muscle, tendon or joint effectors but must be assessed in relation to defective central programmation or dysfunctioning synergy. Posture is the result of a series of successive reflex reactions, and locomotion itself is the result of a series of sequential stimulations and inhibitions originating in the spinal generator controlled by supraspinal centres. Obviously, in man, cortical and subcortical activation is essential as is the activity of the limbic system and the associative zones, together with the basal gangia and the cerebellum. Peripheral proprioception accelerates consciousness of information originating in the muscles, tendons and joints; vestibular and visual input adds further, though redundant, information. Advanced methods of quantifying posture and walking offer a new approach to the analysis of gait disorders. The Bessou locometer analyzes physiological senescence leading to an inconscient strategy which decreases the speed and length of each step. This mechanism might be explained by the aging process leading to non-necrotic cell failure without any specific lesion, vascular for example. Another method is the ELITE system (Elaboratore de Immagini Televisive). This system evaluates the way the subject modelizes and reconstructs his environment. Interesting results have been obtained with postural imbalance induced by visual stimulations.

Aged↗
PubMed1994

Counter irritation test in primary fibromyalgia.

In primary fibromyalgia the main symptom is diffuse pain predominating at tender points which are sensitive to palpation. The aim of this study was to compare the effects on the amplitude of the nociceptive flexion reflex of the lower limb (RIII reflex) of applying painful pressure to the tender points with the effects of the same pressure applied to other points of the body or to the same part of the body in control subjects. This method was chosen because previous studies have shown that it was possible to activate the diffuse noxious inhibitory system using a "counter-irritation" stimulation. Our study was carried out on 18 fibromyalgic patients and on 12 control subjects. During the counter-irritation procedure, consisting of applying pressure with a mechanical dolorimeter to tender points, a clear cut and significant decrease in the amplitude of the RIII response was observed in 6 patients. In conclusion, in view of the subjective nature of the criteria used at present to diagnose primary fibromyalgia, we would like to suggest that a positive counter-irritation test be adopted as a further obligatory criterion, since it has been clearly established that the diffuse noxious inhibitory control responsible for the decrease in the RIII amplitude can be activated only when the subjects undergo intense nociceptive stimulation.

Adult↗
PubMed1994

Contrast sensitivity improvement with sulfamethoxazole and trimethoprim in a patient with Machado-Joseph disease without spasticity.

A double-blind, placebo controlled, cross-over trial of sulfamethoxazole and trimethoprim was performed in a 62-year-old male patient who suffered from Machado-Joseph disease for 25 years. The patient, with cerebellar ataxia, akinetic-rigid syndrome and motor weakness but without any pyramidal features, had been chair-bound for 3 years before the trial. Bactrim therapy markedly improved performance on a physical examination which tested standing and gait, as compared to placebo session. Walker-assisted gait was possible again. For the first time, evaluation of spatio-temporal contrast sensitivity was performed and also revealed an improvement after Bactrim therapy as compared to placebo. These results suggest that Bactrim may be effective in degenerative neurological diseases and that Bactrim may have an overall effect on neurotransmission rather than solely possessing antispastic properties.

Analysis of Variance↗
PubMed1994

A single report of hemiplegic arm stretching related to yawning: further investigation using apomorphine administration.

We observed a stroke patient with an infarct of the internal capsule interrupting the pyramidal tract who stretched his hemiplegic arm during spontaneous and apomorphine-induced yawning. The putative mechanism by which yawning can induce the paradoxical motor response of the plegic arm in the patient might be the functional efficiency of a pathway projecting directly from the stimulated basal ganglia to lower motor systems in the brainstem.

Apomorphine↗
PubMed1994

Intravenous immunoglobulin treatment in patients with motor neuron syndromes associated with anti-GM1 antibodies: a double-blind, placebo-controlled study.

We studied the effects of intravenous immunoglobulin (IVIg) in 12 patients with motor neuron syndromes associated with high titers of anti-GM1 antibodies. Five of the patients had conduction blocks. The study design was a double-blind, placebo-controlled, crossover trial with IVIg (0.4 g/kg body weight per day injected for 5 consecutive days). We evaluated the patients before and 5, 28, and 56 days after drug administration using a computerized analyzer for muscle strength, the Norris scale for disability, motor nerve conduction velocities for patients with conduction blocks, and measurements of immunologic markers. Compared with placebo, IVIg induced a significant increase in muscle strength only in the patients with conduction blocks.

Adult↗
PubMed1994

[What is left of Morvan's fibrillary chorea?].

In 1890, Morvan described a syndrome of myokimia associated with muscle pain, excessive sweating and sleep disorders. The course was severe and the patient died five weeks after the onset. Several cases were published after this first report in the French literature. The last for 10 years the disease seems to have disappeared. In fact, it seems that the progress in electromyography introduced clear definitions of spontaneous muscle discharges (myokimia, neuromyotonic discharges, fibrillations, fasciculations) allowing recognition of a disease characterized by a syndrome of spontaneous and continuous muscle fiber activity associated with cramping, slow relaxation (pseudomyotonia), excessive sweating and stiffness. Different terms have been used to describe this entity: neuromyotonia (Mertens and Zschocke, 1965) or continuous muscle fibre activity (Isaacs, 1961). Classification of these syndromes has to distinguish inherited from acquired forms, idiopathic cases from cases where neuromyotonia is associated with a peripheral neuropathy, a cancer or an immunological disease. Moreover, the frequent occurrence of this later association and recent reports of improvement after plasma exchanges suggest a possible autoimmune aetiology for this group. Finally, we suggest that the term of "Maladie de Morvan" must be used instead of chorée fibrillaire but only concerning patients who exhibit central disorders including insomnia, hallucinations and altered behaviour.

Acrodynia↗
PubMed1994

[Isolated proximal muscular weakness disclosing myasthenic syndrome].

Three cases of chronic limb-girdle myasthenia gravis (one man and two women) are reported. The duration of the disease was three, five and 20 years respectively. None had oculobulbar weakness during this period nor fluctuating symptoms. The primary diagnosis was myopathy in two cases and myelopathy in the other one. In view of this diagnosis, several features were atypical: absence of marked wasting, preservation of tendon reflexes and normal serum creatine kinase activity. Finally, diagnosis of myasthenia gravis was established by the occurrence of a characteristic decremental muscular response to repetitive stimulation and by positive edrophonium test. It seems that the rate of positivity of acetylcholine receptor antibody is lower than in the common form of the disease. Two patients responded to acetylcholinesterase inhibitors and one to high-doses intravenous human immunoglobulins. These and previous cases described in the literature raise the problem of the definition of an unusual form of myasthenia gravis or of a new type of neuromuscular disease characterized by the presence of distinctive changes on muscular biopsies, specially tubular aggregates as in one of our cases. However, this unusual form of chronic limb-girdle weakness has to be recognized because treatments are effective in most cases.

Adult↗