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Biomedical subjects

E Escuret

Publications and source records attributed to E Escuret.

At least 19 recordsLinked to original sources
PubMed1998

[The cerebral venous outflow tract].

It is generally assumed that the jugular veins are the only significant path for cerebral venous drainage. Little attention has been given to the possible role of other venous paths for the cerebral venous outflow. In fact, the meningorachidian venous plexus acts as the major outflow tract of cerebral circulation in the upright position. This phenomenon is linked with postural variations in cerebrospinal fluid pressure. It is difficult to assess the significance of this posterior venous plexus under physiopathologic conditions, which probably depends on the extent of the anastomoses between the two systems.

Cerebral Veins↗
PubMed1995

[Cerebral ischemic cascade].

The pathophysiology of ischaemia depends on the residual cerebral blood flow. As a result, it is different in global ischaemia, when compared with focal ischaemia, where the centre area is surrounded with an area called an ischaemic penumbra. Ischaemia results from a sudden failure in the oxygen and glucose supply. Oxidative phosphorylation fails, a major event that is responsible for all the other reactions. Anaerobic metabolism produces lactate and H+. Cell membrane ionic pumps are inactivated, which results in a breakdown of ionic homeostasis. Ca++ and Na+ penetrate into the cells, as K+ is released. The energy failure causes an extracellular accumulation of excitatory amino-acids, thus eliciting a hyperstimulation of the NMDA receptors. These receptors are hyperactivated as a result of the deterioration in the control systems with, especially, the blockade of the NMDA receptor by Mg++. As a consequence, there is a massive entry of Ca++ into the cell, including a series of enzymatic reactions involving phospholipases, proteases and endonucleases. Reperfusion will cause toxic lesions by producing free radicals, due to the action of arachidonic acid, xanthine oxidase and nitric oxide. The decrease in cell energetic supplies, as well as the overactivation of enzymes and the production of free radicals, result in cell death.

Anaerobiosis↗
PubMed1991

[Sodium gamma-hydroxybutyrate. Certainties and therapeutic potentialities].

Gamma hydroxybutyrate (GHB) is a simple four carbon molecule which is a natural constituent of many mammalian tissues in the central nervous system (CNS) and in several tissues of the body. The synthesis of GHB is not the same in the central nervous system and in peripheral tissues. GHB modifies the rates and/or the levels of the synthesis of several neurotransmitters. Its natural presence in the CNS, its pharmacological effects and its action on various behaviours have raised the problem of GHB as a neurotransmitter. GHB can reduce energy substrate consumption in both brain and peripheral tissues and it can protect these tissues from the damaging effects of anoxia. In conditions of anoxia or excessive metabolic demand endogenous GHB levels rise. GHB seems to act through the endogenous opioid system. GHB natural function would be to induce the state of hibernation in which one can evidence a trance-like state and hypothermia with high rates of GHB. The synthesis of GHB through a reductive process and breakdown through oxidation suggest that it accumulates under hypoxic conditions. On top of its present clinical use as hypnotic, general anesthetic and in neurotraumatology, GHB would have therapeutic applications in states of anoxia that generates amino-acid excitators and free radicals.

Brain↗
PubMed1977

[Action of dibencozide on nitrogen metabolism in immediate and long-term postoperative resuscitation].

The catabolic orientation of the immediate post-aggression phase is aggravated in neurosurgery by the almost routine prescription of corticosteroids. This emphasises the value of any treatment which might limit this orientation. The authors report their experience with the use of dibencozide, with its known facilitating action upon nitrogen assimilation, in the absence of any side effects.

Adult↗
PubMed1977

[Value of brain metabolic studies in post-traumatic coma].

In 34 comatose patients in the acute phase, the mean hemispheric CBF is lowered as well as the CMRO2, with a quite good relation between these values and the coma level and prognostic so. The cerebral response to a PaCO2 range indicates a quite good relation with the coma level (the lowest value in the most severe comas). The cerebral autoregulation study, using Aramine induced hypertension, can separate the cases with a present autoregulation and the cases with a loss of autoregulation (the most severe and the poorest prognosis). In dynamic conditions (variation of the PaCO2 or Aramine induced hypertension), the change in CMRO2 is interesting : rather good prognosis among the patients with a normal metabolic autoregulation - poor prognosis among those whose metabolic autoregulation is lost.

Brain↗
PubMed1976

[Prolonged traumatic and vascular coma: prognostic and therapeutic indications based on hemodynamic and metabolic studies].

From haemodynamic and metabolic investigation of 65 comatose subjects following cranial traumatism or cerebral vascular accident, the following prognostic and therapeutic indications emerged: The isolated increase in oxygen pressure in the jugular vein to above 50 mm Hg, the simultaneous decrease in circulation of the brain to below of 30 ml/100g/min., and of the brain consumption of oxygen to below 1.5 ml/100g/min., combined with a loss of autoregulation and a decrease in carbon dioxide reactivity indicate that prognosis is very poor. Induced arterial hypertension, associated with hyperventilation, partially corrects brain hypoperfusion in coma from bulbo-pontine lesions. Sodium penthiobarbital and sodium gamma hydroxybutyrate and have the effect of reducing oxygen metabolism which might have some therapeutic value during the acute phase of coma. Clomipramine which has a stimulating effect on oxygen metabolism should be kept in reserve for the chronic phase of prolonged coma.

Blood Gas Analysis↗
PubMed1976

[Value of cerebral metabolic exploration in post-traumatic coma states in the acute phase].

The authors report the values of mean hemispheric blood-flow and cerebral arterial consumption they found in 34 neurosurgical comatous cases in acute state. In basal conditions, mean values of mean hemispheric bloodflow and oxygen consumption are lowered. There seems to be a relation between the values found and the comatous stage on one hand, the prognosis on the other hand. The cerebral response to hypercapnia (16 assays) allows to separate 2 groups, one with a noticeable improvement of cerebral bloodflow, the other with only a minimal response. There was no significant variation of cerebral oxygen consumption in both group. Cerebral response to CO2 seems to be clearly related to the stage of coma (low in the most severe cases) but pronostic incidence remained uncertain. A hypertensive test by means of Aramine (18 assays) allows to separate 3 groups : 1 group (8 cases) where the mean hemispheric bloodflow remained stable during hypertension as did the cerebral oxygen consumption -(autoregulation remained unchanged), 1 group (4 cases) where mean hemispheric bloodflow and cerebral oxygen consumption were lowered (excessive autoregulation), 1 group (6 cases) where mean hemispheric bloodflow increases clearly while under Aramine perfusion (loss of autoregulation). Those dynamic tests, either hypercapnic or hypertensive, allow, in comparing oxygen consumption variations with cerebral bloodflow variations, the distinction between : patients where metabolic autoregulation seems maintained (good prognosis) - (10 cases), patients where metabolic regulation is lost with either "luxury perfusion" (14 cases) - poor prognosis, or "insufficient perfusion" (10 cases). The authors are discussing the treatment concerning those last mentioned patients.

Brain↗
PubMed1976

[Study of carbohydrate tolerance without and with corticotherapy].

Using the glucose tolerance test by the intravenous route, from which the coefficients K (CONARD) of carbohydrate assimilation and (BERNIER) of fasting glycogenolysis, are deduced, the authors study the carbohydrate tolerance of neuro-surgical patients in acute and chronic phases, under corticosteroid therapy and without corticosteroid therapy. The role of corticosteroid therapy in the decrease in carbohydrate tolerance reported is discussed ; for comparative purposes, the authors present the study of carbohydrate assimilation in irreversible coma and in patients with advanced neuroplegia.

Adrenal Cortex Hormones↗
PubMed1976

[Plasma cortisol in neurosurgical resuscitation].

The authors study the values of spontaneous cortisonemia in neuro-surgical patients. They analysed the correlations between this parameter and certain clinical criteria (age, etiology, level of consciousness), the duration and nyctohemeral changes in spontaneous hypercortisonism. Furthermore, they presented the values of iatrogenic cortisonemias as a function of increasing doses of hydrocortisone and discussed the possible mechanisms for the disapperance of injected cortisone.

Adolescent↗