[Primary malignant melanoma of vagina]. / Mélanome vaginal primitif.

The primary vaginal melanoma is a rare aggressive tumour with a poor prognosis. The average age at diagnosis is 60, and there are no known risk factors. The establishment of a classification system and treatment protocols are made difficult because there are so few cases. The 5-year survival rate is estimated at no more than ten per cent. We report a case of an inoperable primary vaginal melanoma in a 58-year old woman. There were metastatic lymph nodes in the lumbo-aortic region, but no extension to bone or viscera. She was treated with nivolumab as monotherapy. Clinical and radiological evolution were both favourable, and the treatment was well tolerated.

Le mélanome vaginal primitif est une tumeur rare, agressive et de mauvais pronostic. L'âge moyen lors du diagnostic est de 60 ans et les facteurs de risque sont inconnus. La rareté de cette pathologie complique l'établissement d'un système de classification et d'un protocole de prise en charge. Le taux de survie à 5 ans ne dépasse pas les 10 %. Nous présentons le cas d'une patiente de 58 ans atteinte d'un mélanome vaginal non opérable avec envahissement ganglionnaire lymphatique lombo-aortique sans métastase osseuse ou viscérale. Un traitement par nivolumab est instauré en monothérapie. L'évolution clinique et radiologique est favorable avec une tolérance au traitement satisfaisante.

[POST-CAESAREAN ABDOMINAL WALL ENDOMETRIOSIS PREVENTION]. / PRÉVENTION DE L'ENDOMÉTRIOSE PARIÉTALE POST-CÉSARIENNE.

Abdominal wall endometriosis (AWE) is a rare type of endometriosis. Its pathophysiological pathways are still unknown. It generally occurs after surgical, mainly gynecological or obstetrical, interventions. The incidence of AWE after a caesarean section is around 0.03 to 0.04%. The symptoms are various, but the classical triad includes the presence of a mass, generally painful, associated with a cyclic variation of the symptomatology. The recommended treatment currently remains complete surgical resection of the mass. This article describes three cases of AWE. Each patient had a caesarean section. Their symptoms, however, occurred after various lengths of time and in different circumstances. We will more specifically discuss AWE secondary to cesarean sections, the diagnostic tools, treatment and prevention strategies.

[Intravenous uterine leiomyomatosis with heart extension: a report of one case]. / Léiomyomatose intravasculaire utérine avec atteinte cardiaque : à propos d'un cas.

Uterine intravenous leiomyomatosis is a rare benign tumor, whose diagnosis of certainty is histological. It is characterized by its potential of intravascular extension with possibility of cardiac localisation imposing a complete surgical removal and a suitable imagery postoperatively. We report the case of a 63-year-old patient, presenting a cardiac extension complicating a LIV, by which we will discuss the diagnosis aspects, prognosis and therapeutic of this pathology.

Noradrenergic modulation of subthalamic nucleus activity in human: metoprolol reduces spiking activity in microelectrode recordings during deep brain stimulation surgery for Parkinson's disease.

BACKGROUND: Reversible changes in subthalamic nucleus (STN) activity, detected by microelectrode recording (MER), are reported in three patients who received an intravenous betablocker, metoprolol, during deep brain stimulation (DBS) for Parkinson's disease (PD). METHODS: Metoprolol (MP) was given intravenously to reduce blood pressure during surgery. Systolic blood pressure dropped by 4, 11 and 17%, indicating a systemic beta - adrenoceptor blocking effect. FINDINGS: In all patients, the bursting spiking activity of the STN was temporarily suppressed, after the application of MP. Unexpectedly, a transient reduction in Parkinson symptoms (rigidity) was recorded during suppression of STN spiking activity in patient 2. CONCLUSION: The reversible suppression of STN activity and Parkinson symptoms with the beta1-selective adrenoceptor antagonist MP has not been reported. It supports the theory, that--as recently reported in the rat--the human STN is influenced by adrenergic inputs. This report supports the possible application of adrenergic antagonist drugs for the use in Parkinson's disease and advocates additional neurophysiological and pharmacological research in this field.

In vivo magnetic and electric recordings from nerve bundles and single motor units in mammalian skeletal muscle. Correlations with muscle force.

Recent advances in the technology of recording magnetic fields associated with electric current flow in biological tissues have provided a means of examining action currents that is more direct and possibly more accurate than conventional electrical recording. Magnetic recordings are relatively insensitive to muscle movement, and, because the recording probes are not directly connected to the tissue, distortions of the data due to changes in the electrochemical interface between the probes and the tissue are eliminated. In vivo magnetic recordings of action currents of rat common peroneal nerve and extensor digitorum longus (EDL) muscle were obtained by a new magnetic probe and amplifier system that operates within the physiological temperature range. The magnetically recorded waveforms were compared with those obtained simultaneously by conventional, extracellular recording techniques. We used the amplitude of EDL twitch force (an index of stimulus strength) generated in response to graded stimulation of the common peroneal nerve to enable us to compare the amplitudes of magnetically recorded nerve and muscle compound action currents (NCACs and MCACs, respectively) with the amplitudes of electrically recorded nerve compound action potentials (NCAPs). High, positive correlations to stimulus strength were found for NCACs (r = 0.998), MCACs (r = 0.974), and NCAPs (r = 0.998). We also computed the correlations of EDL single motor unit twitch force with magnetically recorded single motor unit compound action currents (SMUCACs) and electrically recorded single motor unit compound action potentials (SMUCAPs) obtained with both a ring electrode and a straight wire serving as a point electrode. Only the SMUCACs had a relatively strong positive correlation (r = 0.768) with EDL twitch force. Correlations for ring and wire electrode-recorded SMUCAPs were 0.565 and -0.366, respectively. This study adds a relatively direct examination of action currents to the characterization of the normal biophysical properties of peripheral nerve, muscle, and muscle single motor units.

Arthritis and heart lesions. A study of 25 cases with pericarditis or valvular lesions associated to inflammatory joint disease.

Clinical and laboratory data of 25 patients with inflammatory joint disease and pericarditis or valvular heart disease are reviewed. The patients were divided in two groups: 11 presented pericarditis and 14 valvular heart disease. The patients studied presented a spectrum of diseases ranging from classical sero-positive rheumatoid arthritis to ankylosing spondylitis. Acute rheumatic fever was in no case the actual joint disease. In contrast to the patients with valvular heart disease nearly all patients with pericarditis were rheumatoid arthritis factor positive and signs of a generalized systemic disease with vasculitis were also more frequent. In the pericarditis group there was no sex difference in contrast to the valvular group where females were more often affected. The heart lesions were usually detected late in the course of the chronic joint disease. Valvular heart disease occurs not only in ankylosing spondylitis but also in rheumatoid arthritis, usually the sero-negative type. In the light of a survey of the literature, the pertinent findings are discussed.

A comparison of two models for calculating the electrical potential in skeletal muscle.

We compare two models for calculating the extracellular electrical potential in skeletal muscle bundles: one a bidomain model, and the other a model using spatial and temporal frequency-dependent conductivities. Under some conditions the two models are nearly identical. However, under other conditions the model using frequency-dependent conductivities provides a more accurate description of the tissue. The bidomain model, having been developed to describe syncytial tissues like cardiac muscle, fails to provide a general description of skeletal muscle bundles due to the non-syncytial nature of skeletal muscle.

A model for compound action potentials and currents in a nerve bundle. I: The forward calculation.

We describe a model for the Compound Action Currents (CACs) and Compound Action Potentials (CAPs) produced by a peripheral nerve bundle in vitro. The Single Fiber Action Currents (SFACs) and the extracellular Single Fiber Action Potentials (SFAPs) are calculated using a generalized volume conduction model. Frequency-dependent conductivities, variations in the intracellular action potentials with recording temperature and axon conduction velocity, and the effects of axonal myelination are incorporated into the volume conduction calculation. We demonstrate how the propagation distance and the recording radius affect the simulated Compound Action Signals (CASs) of various nerve bundles. We also demonstrate how the frequency-dependent and -independent conductivities affect the CASs simulated by our model. For this simulation, some of the parameters for the nerve bundles and Conduction Velocity Distributions (CVDs) were obtained from the literature. In accompanying papers, we use the simulated CASs to investigate the effects of variations in the model parameters on the CVDs predicted by our inverse model.

A model for compound action potentials and currents in a nerve bundle. III: A comparison of the conduction velocity distributions calculated from compound action currents and potentials.

In this paper, we present the experimentally measured Compound Action Current (CACs) and Compound Action Potentials (CAPs) from frog sciatic nerves and earthworm nerve cords. We used histologically prepared cross sections of these nerve bundles to determine the distribution of fiber diameters. A modified volume conduction model that includes frequency-dependent conductivities was used to compute the Single Fiber Action Signals (SFASs). The recorded CACs and CAPs are used to predict the Conduction Velocity Distributions (CVDs) from the nerve bundles. The predicted CVDs are then compared with the histological CVDs. Analysis of Compound Action Signals from the three giant axons in the earthworm nerve cord and microelectrode data for the transmembrane action potential demonstrate the validity of our mathematical model. We found that the CVDs predicted from the recorded CACs and CAPs differ from the histological CVD for a variety of reasons. The validity of the assumption of a linear relationship between axon diameter and conduction velocity of a propagating action signal was investigated using CVDs from both the CAC and CAP. Variations of the CVDs with the propagation distance of the CASs and the recording temperature were investigated.

Multicentre European study of thalamic stimulation in parkinsonian and essential tremor.

OBJECTIVES: Thalamic stimulation has been proposed to treat disabling tremor. The aims of this multicentre study were to evaluate the efficacy and the morbidity of thalamic stimulation in a large number of patients with parkinsonian or essential tremor. METHODS: One hundred and eleven patients were included in the study and 110 were implanted either unilaterally or bilaterally. Patients were evaluated with clinical scales, before and up to 12 months after surgery. RESULTS: Upper and lower limb tremor scores were reduced in both groups. Eighty five per cent of the electrodes satisfied the arbitrary criteria of two point reduction in rest tremor reduction in the parkinsonian tremor group and 89% for postural tremor reduction in the essential tremor group. In the parkinsonian tremor group, limb akinesia and limb rigidity scores were moderately but significantly reduced. Axial scores were unchanged. In the essential tremor group, head tremor was significantly reduced only at 3 months and voice tremor was non-significantly reduced. Activities of daily living were improved in both groups. Changes in medication were moderate. Adverse effects related to the surgery were mild and reversible. CONCLUSIONS: Thalamic stimulation was shown to be an effective and relatively safe treatment for disabling tremor. This procedure initially applied in a very limited number of centres has been successfully used in 13 participating centres.

The different intracellular action potentials of fast and slow muscle fibres.

The time course of the intracellular action potential was studied quantitatively, because it is an important factor in the generation of electromyographic signals. In in vivo preparations of the m. EDL and m. soleus of the rat single motor units were stimulated and intracellular action potentials were recorded in muscle fibres belonging to those motor units. In this arrangement it was possible to relate the intracellular action potential to the fibre type. The intracellular action potentials of fast twitch glycolytic (FTG) EDL and of slow soleus fibres were described, using 8 characteristics. All characteristics but one differed significantly between the two fibre populations. Comparing characteristics of intracellular action potentials of FTG fibres with slow fibres, it is concluded that: the resting membrane potential is more negative; the amplitude of the action potential is larger; the maximum rates of depolarization and repolarization are higher; and the shape of the repolarization phase is more variable.

Relevance of hydroxyproline excretion to bone metastasis in breast cancer.

In 181 consecutive patients with breast cancer, urinary hydroxyproline excretion has been critically evaluated in conjunction with clinical, biochemical, radiological and scintigraphic parameters. The urinary hydroxyproline/creatinine ratio is a sensitive index of the presence of bone metastases. Urinary hydroxyproline excretion is a reliable method of selecting those patients whose elevated serum alkaline phosphatase is secondary to bone disease rather than liver idsease. The estimation of hydroxyproline excretion furthermore gives information on the activity of bone metastasis, and its response to treatment, which cannot be given by radiological or scintigraphic methods. It is doubtful whether urinary hydroxyproline estimation will help to detect bone metastases before they are apparent on scintigrams. When the bone scan is doubtful, as often occurs in older subjects, hydroxyproline excretion has been found to be helpful in classifying the patient. When scintigraphy is not available, an elevation of hydroxyproline excretion, together with an elevation of Ca/cr ratio or alkaline phosphatase activity, may pre-date by several months the radiological demonstration of osseous metastases.

Theoretical performance and clinical evaluation of transverse tripolar spinal cord stimulation.

A new type of spinal cord stimulation electrode, providing contact combinations with a transverse orientation, is presented. Electrodes were implanted in the cervical area (C4-C5) of two chronic pain patients and the stimulation results were subsequently simulated with a computer model consisting of a volume conductor model and active nerve fiber models. For various contact combinations a good match was obtained between the modeling results and the measurement data with respect to load resistance (less than 20% difference), perception thresholds (16% difference), asymmetry of paresthesia (significant correlation) and paresthesia distributions (weak correlation). The transversally oriented combinations provided the possibility to select either a preferential dorsal column stimulation, a preferential dorsal root stimulation or a mixed stimulation. The (a)symmetry of paresthesia could largely be affected in a predictable way by the selection of contact combinations as well. The transverse tripolar combination was shown to give a higher selectivity of paresthesia than monopolar and longitudinal dipolar combinations, at the cost of an increased current (more than twice).

Subthalamic nucleus stimulation for advanced Parkinson's disease: how to find a far medial STN.

In a patient with advanced Parkinson's disease, an anatomically deviant far medial subthalamic nucleus (STN) posed problems in the placement of DBS electrodes for chronic high frequency (HF) stimulation despite the use of multimodal targeting with 1) statistical atlas data, 2) T (2)-weighted (T (2)W) magnetic resonance imaging (MRI), 3) microelectrode recording, and 4) clinical testing with macro stimulation. Diagnostic T (2)W MRI suggested that the patient's STN was in a typical location and seemed to confirm the statistical atlas-based planning. Intraoperatively, cell activity recording (MER) with five parallel electrodes could not reveal any STN typical activity profile and electrical stimulation was not able to disclose a medial or lateral displacement of the electrodes. The operation was discontinued and postoperative stereotactic CT confirmed that the correct target area had been approached during the operation. Postoperative T (2)W MRI now disclosed a left STN which was 2 mm medial of the initial target and lead to a further medial target definition and finally to a successful DBS placement. In conclusion, finding a deep seated DBS target like the STN can be difficult in cases with an extremely deviant anatomy even if reiterative sophisticated multimodal planning is used. In the presented case we applied the integrated information from intraoperative MER, macrostimulation and postoperative imaging work-up and were able to complete DBS implantation successfully.

A comparison of electric and magnetic compound action signals as quantitative assays of peripheral nerve regeneration.

The evaluation of peripheral nerve regeneration is of great interest in clinical as well as in experimental situations. However, there are few techniques that give early and quantitative information on the status of the regeneration process. If quantitative assays would be available, different surgical techniques and medications could be evaluated more accurately in relation to axonal ingrowth and functional recovery. The purpose of this study was to investigate the merits of nerve compound action signals (NCASs) recorded electrically and signals recorded with a novel magnetic recording technique. We compared the two techniques in the rabbit peroneal nerve, 2, 4, 6, and 8 weeks after a nerve reconstruction. Our conclusions are that the signals recorded with the magnetic sensor are far more reproducible and less prone to stimulus artifact than the electrically recorded signals. Furthermore, the magnetic recording shows that the number of axons that have regenerated increases with time. Previously, this could only be determined with histological studies. Other ingrowth parameters that can be quantified are the average ingrowth distance, and the variation between axons in ingrowth velocity.

Calculation and registration of the same motor unit action potential.

In order to increase insight into the electrical phenomena of active motor units, a computer simulation model has been developed. With this model motor unit action potentials (MUAPs) have been calculated. The model has been based on the superposition of the muscle fibre potentials of the fibres of one motor unit. For verification, calculated MUAPs have been compared with the matching recorded MUAPs. During experiments one motor unit was stimulated and the MUAP of this unit was measured with intramuscular wire electrodes. After the experiments the positions of the activated fibres of this unit and of the electrodes were determined by means of histochemical techniques. Other parameters were derived from other experiments or the literature. Using the obtained set of parameters in the model MUAPs were calculated. These MUAPs were compared with the measured MUAPs. From this comparison it has been concluded that the model predicts the MUAP to an appreciable degree. The results clearly show the dominating effect of muscle fibres in close vicinity of the electrode and the important effect of the activation moment of those fibres on the shape of the MUAP.