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Biomedical subjects

M Barge

Publications and source records attributed to M Barge.

18 recordsLinked to original sources
PubMed1979

Correlative study between computerized transverse scanning and stereoimpedoencephalography in space-occupying lesions of the brain.

Stereoimpedoencephalography (SIEG) is routinely used by the authors during stereotactic investigations of glial brain tumours prior to stereotactic implantation of isotopes or prior to conventional surgery: the brain tissue impedance is measured along a probe track according to the four electrodes impedance technique. The correlation between the tissue structures and the corresponding impedance values has been studied by comparison with the CATScan data reported on the stereotactic schedules; impedance values are influenced by changes in arterial pCO2 and also by other unknown factors; in order to avoid these uninterpretable changes of the impedance, the recorded values have been normalized with respect to the average impedance along a control track in the normal hemisphere. As a rule, the impedance profile exhibits a "hole" at the site of the pathological processes like tumours as well as surrounding oedema, and the delimitation of the pathological area is very similar to that obtained by the CATScan. There is a good linear correlation between the values of normalized impedance and the x-ray absorption as given by the computer listing of the CATScan. Lastly, statistical values of normalized impedances are determined for the main structures of the brain, showing that the tumour tissue has an impedance equal to half the impedance of the normal tissue.

Brain Neoplasms↗
PubMed1978

[Delineation of brain tumors by stereo-impedo-encephalography (SIEG) (author's transl)].

Authors describe the SEEG technique which is routinely used during stereotactic investigations of brain tumors. By the way of the Talairach's stereoencephalographic electrodes, the brain tissue impedance is measured along the probe trajectory with a four electrode impedancemeter (0.25 mA; 5 KHz). The impedance profile provides a good pattern of the brain structures which are crossed; in pathological areas, the impedance significantly decreases as well in gliomas as in edema; cysts and CSF spaces also decrease the recorded impedance. As a contrary, metastases and meningiomas increase the impedance. SEEG appears to be a sharp method for stereotactic delineation of the brain tumors; a larger series as well as the real-imaginary decomposition of the impedance are needed for a best selectivity of the method.

Adult↗
PubMed1978

[Mesodiencephalic level of severe head injuries (author's transl)].

From the study of 65 severe traumatic comas, the authors describe the syndrome of mesodiencephalic dysfunction, because of its frequency and its particular clinical signs. This peculiar level of loss of consciousness is characterized by a coma without mimic and without awakening after painful stimulation, by a stereotyped motor pattern in extension, by a perseverance of the photomotor reflex, while fronto-orbicular and vertical oculo-vestibular reflexes are lacking. This level of deterioration appears to be a critical point in the natural history of comatose patients. If this level is not surpassed, the probability of early death due to evolutive neurological lesion is low (18%). One half of these patients have a good prognosis, more than 75% have an excellent recovery. This high probability of recovery is decreased by a half when the level of mesencephalic dysfunction is reached.

Brain Injuries↗
PubMed1978

[Two cases of pericranial sinuses (author's transl)].

The authors report two cases of "sinus pericranii" a rare vascular tumor of the skull, communicating with the meningeal veins or with the dural sinuses. The partial reduction in size of the tumor in the sitting position may aid the clinical diagnosis. The X ray diagnosis is highly enhanced by the direct injection of contrast medium into the tumor, leading to the visualization of the outflow in the miningeal veins, while external carotid angiography is normal. Step by step coagulation of the verious supply coming through the skull allows a non-bleeding surgical excision.

Child, Preschool↗
PubMed1978

[Intracranial pressure. IV - Relationships with post capillary vascular pressures (author's transl)].

The authors have demonstrated experimentally in dogs that, in all cases, the cortical venous pressure (Pvco) is higher than the intracranial pressure (PIC), which always remains higher than the sagittal sinus venous pressure (PSLS). The difference between Pvco and PIC remains statistically equal to 8 mm Hg and can be explained by the "Vascular Waterfall" phenomenon; during Queckenstedt's test, the intracranial venous volume does not change, and is not the cause for the increase of PIC; this increase is due to the constancy of the difference between PIC and PSLS, which is induced by the resorption of CSF through the arachnoïd villi. Increases in Pvco and PIC are shown to be equal to 70% and &2% respectively of the change in PSLS. Any other factor that increases PIC (injections in the cisterna magna, pharmacological effects) does not change PSLS, which remains equal to zero. As long as the cerebral blood flow is constant, the increase in cerebro-vascular resistance of the veins at the site of their junction to the sagittal sinus must be compensated upstream by a vasodilatation, which leads to a new distribution of the pressures along the cerebro-vascular bed.

Animals↗
PubMed1977

[Primary "muscle" tumors or tumors with a myosarcomatous component of the central nervous system. General review and attempt at classification based on 2 anatomo-clinical observations].

The authors report the first two French cases of primary rabdomyosarcoma of the central nervous system. They then review the literature on muscle tumours or primary myosarcomas of the nervous system of which 29 cases have now been published. From the point of view of morphology and classification, one should distinguish firstly, purely mesenchymatous tumours (rhabdomyosarcomas, leiosarcoma, mesenchymoma) and secondly, composite tumours of connective tissue or spino-epithelial tumours (medullomyoblastomas, neuromyoblastomas, gliomyosarcomas). Their histogenesis occurs from the ectomesenchyme of the neural crests.

Age Factors↗
PubMed1976

Rheographic assessment of cerebral blood volume and correlations with changes in intracranial pressure.

The authors present a four electrode rheographic technique for simiquantitative continuous measurement of CBV, by examining changes in cerebral tissue impedance induced by changes in blood content of the brain parenchyma. Correlation between the data obtained and ICP measurements permits conclusions regarding the behaviour of the cerebral blood bed. pCO2 regulates CBV, and the phenomenon is reversible according to a hystereris shaped time course in acute experiments. The rebound of ICP after sudden injections of CSF into the cisterna magna is of a vasogenic nature. Changes in CSF volume induce contrary changes in CBV. Pharmacological effects can be studied. The validity of the method is discussed.

Animals↗
PubMed1976

[Hyperproduction of CSF in choroid plexus papillomas in children].

Two cases of papilloma of the choroid plexus in children, one in the fourth ventricle and the other in the central part of the left lateral ventricle, are reported. Hyperproduction of CSF could be suspected in the first case by the productive character of pre-operative external ventricular drainage and demonstrated in the second by measurement of pre and post-operative flow rates through a ventriculo-peritoneal bypass which had been installed previously. The origin of this over-production of CSF is discussed, in the pathogenesis of hydrocephalus, in comparison with other factors such as subarachnoid haemorrhage, hyperproteinorachia impairing the resorption of CSF.

Cerebellar Ataxia↗
PubMed1975

[Intracranial pressure. II. Experimental verification of a mathematical model].

The authors report the results of experiments (performed on the dog in vitro and in vivo) which were designed to verify hypotheses made concerning vascular elasticity and characteristics of CSF resorption, as well as to test the validity of a mathematical model that was described in a previous paper. The authors concluded that the equations of the model account for most of the phenomena satisfactorily, but fail to predict a rebound phenomena which occurs after sudden injections in the cisterna magna. The elasticity coefficient S appears to be constant over a range of 200 mm Hg. On the other hand, the filtration coefficient K depends upon pressure, probably due to morphological changes in the size and shape of the CSF valves. These discrepancies are taken into account in a more general model that is presented in the following paper.

Animals↗
PubMed1975

[Intracranial pressure. III. Trial generalized theory].

The authors reported previously an elementary mathematical model of intracranial pressure (ICP) as well as result from an experimental verification of the model. The experimental tests revealed that certain factors had been neglected in the theoretical formation, and the present article offers an expanded version of model which takes into account those factors: changes in the formation of the CSF as a function of ICP; cerebral vasomotricity; cortical and sinusal venous pressures, and variations of the filtration coefficient of the subarachnoidal spaces. A generalized mathematical model of ICP, in the form of four equations, is proposed. The major aspects of both normal and pathological ICP are studied in the light of this model, and are integrated into a generalized theory.

Brain Death↗
PubMedDate not supplied

[Semiologic aspects of traumatic coma (author's transl)].

After studying 85 patients with severe traumatic coma and reviewing the published literature, the authors propose a simple clinical procedure for the diagnostic of such cases. This classification is based on signs without any ambiguity, easily recognized by different physicians, and of pathognomonic significance. These include reaction to pain, testing four reflexes integrated at different levels in the brain stem, pupil morphology, and spontaneous ocular movements. The clinical features corresponding to different levels of dysfunction in the brain are described and their characteristics outlined. The importance of motor reactivity to pain associated to the brain stem reflexes (fronto-orbicular, photomotor, horizontal and vertical oculo-encephalic) is stressed.

Brain Stem↗
PubMedDate not supplied

[EEG and clinical study of 107 patients with acute severe traumatic comas (author's transl)].

The authors describe the EEG recordings of 107 patients with acute severe cranial trauma and signs of axial lesions. The initial EEG included: sleep patterns, alternating tracings, alpha band tracings which were either nonreactive pseudo-alpha or modulated alpha often reactive, and diffuse slow wave tracings. They found no particular tracing corresponding to a precise level of rostrocaudal destructuration, but some associations were seen more frequently. EEG sleep patterns and alternating tracings were never observed in brain stem lesions, the activity recorded being of low voltage, rigid, and non-reactive. The presence of spontaneous fluctuations (with sleep rhythms in some cases) and reactivity in other levels (mesodiencephalic junction, diencephalic and cortical-subcortical) are good prognostic signs. Focalised EEG signs are seen especially in the more rostral levels.

Brain Injuries↗
PubMedDate not supplied

[Diagnostic and prognostic value of the brain stem reflexes in severe post-traumatic coma].

Authors study the neurological evolution of 50 cases of traumatic coma and recognize 5 misfunction levels corresponding to five steps of rostrocaudal deterioration. The level 1 (cortico-sub-cortical) is defined by the persistence of the mimic and flexion response to painful stimulation. The level 2 (diencephalic) is characterized by stereotypic responses to pain and lack of mimic. At these two levels, the fronto-orbicular and vertical oculo-vestibular reflexes are persistent. These reflexes disappear when the status impair caudodal to the level 3 (meso-diencephalix junction). The photomotor reflex disappear at the level 4 (mesencephalic), where the motor response to pain may be very poor, or may be a bilateral extension. The horizontal oculo-vestibular reflex is always persistent, except for the level 5 corresponding to a pontine lesion. The meso-diencephalic level 3 appears to be a critical impairment point: as long as the level is not overpassed, the half of the patients do improve and 10% only die. More than 75% of those who improve from this level have an excellent recovery. The restructuration probability is diminished by the half when the level of mesencephalic misfunction is reached.

Brain↗