Biomedical subjects
J Siegfried
Publications and source records attributed to J Siegfried.
Therapeutic value of Madopar HBS: judgment after 2 years experience.
The study included 19 parkinsonian patients presenting with fluctuations in motor performance after L-dopa therapy (9.9 years on average, range 6 months to 17 years) and 2 other patients not pretreated with L-dopa. In all patients of the first group, after 3 months on stable 'optimal' dosage schedule, the previous L-dopa treatment was abruptly replaced, dose for dose, from one day to another by Madopar HBS, a new controlled-release form of Madopar. The first clinical assessment was performed just before the beginning of the HBS treatment. Then, 4-6 weeks were allowed to optimize the dosage schedule of Madopar HBS before performing a second assessment. Long-term therapeutic effects were systematically evaluated after 6 and 12 months. Catamnestic evaluation took place at the last check-up for patients treated for more than 1 year. Of the 19 patients with fluctuations 1 dropped out after 7 days due to lack of cooperation. Thus, 18 of these patients were evaluable. At the end of the dose adaptation phase 12 patients (2/3) were better controlled by the new dosage form and were eligible for a long-term follow-up aiming to evaluate the maintenance of the benefit. It was concluded that in most of the patients the initial benefit was maintained during 1 year and even up to 2 years and 7 months for some of them. The best results were obtained in patients with mild to moderate forms of fluctuations (early stage). Positive results in de novo cases need confirmation.
Ventricular cerebrospinal fluid concentrations of putative amino acid transmitters in Parkinson's disease and other disorders.
Concentrations of putative neuroactive substances glutamate, aspartate, gamma-aminobutyric acid, glycine, proline and ethanolamine were determined in ventricular cerebrospinal fluid collected in patients suffering from Parkinson's disease, pain syndromes or cerebellar tremor. Values are similar to those given in the literature for lumbar cerebrospinal fluid. A decrease in gamma-aminobutyric acid in Parkinson patients, as reported in lumbar cerebrospinal fluid, could not be observed. Further evidence for a rostro-caudal gradient for gamma-aminobutyric acid is supplied. New insights into pathophysiological mechanisms in any of the investigated syndromes may not be derived.
A simple in vitro method to study the trigeminal ganglion.
This report describes a simple in vitro method to harvest and study the electrophysiological properties of the trigeminal ganglion of the rat. In suction electrode recordings from the proximal nerve end, two distinct peaks are identified in the compound action potential evoked by electrical stimulation of the distal nerve. gamma-Aminobutyric acid (GABA), added to the perfusion fluid, caused a positive shift in the DC potential (depolarization) and a partially selective decrease in the amplitude of the slow-conduction peak. Reversible antagonism of the GABA effect by picrotoxin and bicuculline suggests that both responses are receptor mediated. There was no response to carbamazepine or L-baclofen, suggesting that ganglionic polarization does not play a major role in the action of these drugs in trigeminal neuralgia.
[Lumbosacral fibrosis (spinal epiduro-arachnoiditis) and its treatment by spinal cord electrostimulation].
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[Effect of stimulation of the sensory nucleus of the thalamus on dyskinesia and spasticity].
Intermittent electrical stimulation of thalamus sensory nucleus effectively controlled dyskinesiae in 4 patients with Dejerine-Roussy's painful thalamic syndrome, and clonus of legs in 2 patients with post-traumatic medullary paraplegia. Results of long-term follow-up of these 6 cases, with movements controlled by implantation of a system of electrical stimulation of the thalamus sensory nucleus, are reviewed.
Foramen ovale electrodes: a new technique enabling presurgical evaluation of patients with mesiobasal temporal lobe seizures.
A recently developed technique to record from the mesiobasal aspect of the temporal lobes by subdural electrodes inserted through the foramen ovale is described. Experience with this technique in 13 candidates for surgical epilepsy therapy is presented. Our results indicate that interictal epileptiform potentials as well as ictal discharges are reliably picked up by the foramen ovale electrode whenever nucleus amygdallae, hippocampus and parahippocampal gyrus show synchronous epileptic activity. The advantages of this technique are discussed.
[Functional neurosurgery of cerebral palsy].
In 1983, approximately 40 000 patients in France and 5 760 patients in Switzerland suffered from cerebral palsy, representing more than 0.1% of their respective populations. The functional disability of these patients is particularly impressive and emphasizes the medical, social and economic importance of this problem. The term cerebral palsy is restricted to non-progressive disorders of motor function, already observed at an early age and due to cerebral lesions. These motor disorders can be of paretic, dystonic and dyskinetic nature. Their epidemiology, classification, etiology, pathology, early diagnosis and evolution are extensively reviewed by Th. Deonna. The difficulty in evaluation of treatment is the absence of a generally accepted rating scale. G. Broggi has proposed one on the basis of a large experience which could serve in the future for more objective evaluation. This monograph is devoted to the functional neurosurgical treatment of cerebral palsy. Physiotherapy and rehabilitation are part of the basic treatment of cerebral palsy, and must be continued after any neurosurgical treatment. Various conservative methods of treatment and their neurophysiological rationale are mentioned by P. Claverie. Some technical devices which improve the neurological deficits and facilitate rehabilitation are presented. Radiculotomies and neurotomies are probably the oldest neurosurgical operations for the treatment of spasticity. The neurophysiological and neuroanatomical basis of this therapeutic approach are treated in the review of the material from the neurosurgical department of Montpellier. Sixty cases were collected and the results analysed according to the type of operation (posterior radiculotomy, anterior radiculotomy, mixed) performed. Stereotactic thalamotomies and subthalamotomies are believed to be the best neurosurgical method to treat the tremor and improve other dyskinesias and hyperkinesias. The technique and a personal review of 49 cases of cerebral palsy are presented. The long-term follow-up in this study demonstrates that this type of operation markedly improves the functional disability of patients with moderate hyperkinesias, moderately improves patients severely affected, but also demonstrates that possible side effects cannot be ignored. Review of the literature indicates the difficulty in interpretation of results due to a lack of objective evaluation. Nevertheless, stereotactic thalamotomy can still be recommended when tremor and rigidity are the most prominent symptoms. Stereotactic dentatotomies in the treatment of spasticity were very popular 20 years ago, but have been largely forgotten for nearly a decade.(ABSTRACT TRUNCATED AT 400 WORDS)
[Thalamic pain syndrome. Clinico-radiologic correlations and treatment by intermittent stimulation of the sensory nuclei of the thalamus].
The thalamic pain syndrome is classically due to a softening of sensory thalamic nuclei. In a series of 10 patients treated between 1977 and 1984 by the intermittent stimulation of the nuclei ventroposterior thalami, the CT-Scan showed in 7 cases the thalamic lesions and in 3 cases a parietal one. The clinical manifestations of theses 2 groups can be individualised. The therapeutical results with long follow-up are moderate with 2 improvements of pain of more than 50%, 5 of less than 50% and 3 failures. The place of this technique is discussed.
Neurosurgical treatment of cancer pain.
Neurosurgical pain operations in carcinoma patients should always be considered when conservative treatment methods fail or pain relief can be attained only at the cost of undesired side effects. The therapeutic spectrum of neurosurgery has been appreciably extended in recent years. Due to the introduction of percutaneous surgery methods, the operations have become less burdensome, so that carcinoma patients who were formerly regarded as inoperable can also be given neurosurgical pain treatment. The advances in neurophysiology have led to a better understanding of pain mechanisms, in consequence of which the various possibilities of treatment can be employed more specifically with prospects of better treatment results. The spectrum of neurosurgical treatment extends from destructive measures (rhizotomies, cordotomies, thalamotomies, neurolytics) via intrathecal administration of morphine-like substances to the augmentative nondestructive neurostimulation techniques. Despite the advances in conservative therapy of cancer pain, in many cases, a neurosurgical procedure is most efficacious in controlling carcinoma pain.
[Neurosurgical methods for the alleviation of pain].
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Suprasellar arachnoidal cyst as a cause of early puberty.
Puberty developed in a boy before age 12 years despite a marked delay in skeletal development. A large suprasellar arachnoidal cyst was found. Such cysts may be a cause of precocious puberty.
Analysis of carbamazepine actions in hippocampal slices of the rat.
Carbamazepine at therapeutic concentrations has a strong inhibitory effect on the spontaneous field bursts of the CA 1 region of rat hippocampal slices in low-Ca2+, high-Mg2+ solution. A reduction of excitability and synaptic transmission as well as no effect on posttetanic potentiation in the rat hippocampal slice by carbamazepine agrees with previous studies on spinal cord and peripheral nerve. Carbamazepine left synaptic inhibition and hyperpolarizing afterpotentials unaltered while these inhibitory processes were markedly enhanced by pentobarbital and adenosine, respectively. The spontaneous field bursts are, at least in part, synchronized by ephaptic transmission and may serve as a model of epilepsy and trigeminal neuralgia. The clinical effectiveness of carbamazepine in these two ailments may be explained by a suppression of this pathological synchronization.
Trigeminal neuralgia--earlier referral for surgery.
Patients with trigeminal neuralgia may be treated in many ways before referral for definitive surgery. This aspect has been looked at in a group of 140 consecutive patients. Patients on prolonged medication have been studied with respect to the period over which the pain occurred and the amount of carbamazepine taken. Earlier referral for surgery is recommended for some of these patients and guidelines are given.
The role of stereotactic amygdalotomy in the treatment of temporal lobe epilepsy associated with behavioral disorders.
The efficacy of bilateral stereotactic amygdalotomy for the treatment of aggressive behavioral disorders has been evaluated in a retrospective study of 67 cases. In addition 4 cases with complex partial seizures accompanied by aggressive outbursts revealing a unilateral epileptogenic focus in the amygdala or periamygdala region during preoperative stereoelectroencephalographic (SEEG) evaluation received a unilateral stereotactic amygdalotomy. Long-term follow-up of these 4 cases shows that 3 patients had considerable improvement in seizure frequency and severity as well as behavioral disturbances. The results in the remaining patients evaluated by surface EEG were inconclusive.
Multipolar hollow-core electrode for brain recordings.
A multicontact macroelectrode for brain recordings is described. Its hollow-core structure and slightly recessed contacts allow the electrode to be guided with a central stylet for minimal tissue trauma. The helical design of the electrode is characterized by high fatigue resistance and high flexibility allowing movement with the brain and preventing slicing through tissue. Clinical results have been obtained on epileptic patients.
Intracerebral electrode implantation system. Technical note.
A new technique for deep-brain electrode implantation is described. A very flexible nontraumatic electrode guided by a central stylet and a new electrode head-fixation screw are the two unique features of this system. Electrodes can be guided precisely and their watertight fixation to the bone by means of the special screw is reliable and totally reversible. The system has been designed to fit most of the stereotaxic frames currently in use.
Lumbosacral spinal fibrosis (spinal arachnoiditis). Its diagnosis and treatment by spinal cord stimulation.
From 1973 to 1981, 94 patients suffering from low-back pain, with or without spread into the lower extremities, were candidates for therapeutic spinal cord stimulation. The etiology of pain in all cases was lumbosacral spinal fibrosis due to multiple myelographies and surgical interventions on the lumbar spine. The long-term results, based on a four-year follow-up, reveal a 60% subjective improvement of pain, a 40% substantial reduction of medication, and a 26% increase in working capacity. The concept of spinal arachnoiditis is reviewed and the term lumbosacral spinal fibrosis proposed. The treatment of this chronic painful and disabling disease is discussed.