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Biomedical subjects

F Cohadon

Publications and source records attributed to F Cohadon.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

[Anatomical findings in 30 cases of acute severe traumatic coma (author's transl)].

A variety of lesions of varying complexity were noted during pathological examinations of the brain in 30 cases of acute severe traumatic coma, of whom 27 survived for less than 10 days. "Diffuse brain damage" were present in all cases and contusions were frequently noted (83 p. 100). The lesions appear immediately after, and are directly related to the injury. Ischemic lesions were present in 66 p. 100 of cases and their mechanisms of production are various and interwoven. The frequency of respiratory difficulties associated with brain injuries is stressed. Two thirds of the cases with brain stem lesions (80 p. 100) were secondary to phenomena related to trans-tentorial herniation. Clinical examinations of these patients with acute severe coma demonstrates the difficulties encountered in assessing prognosis based on clinical findings within the first 48 hours.

Brain↗
PubMedDate not supplied

The early phase of cryogenic lesions: an experimental model of seizures updated.

Following cryogenic lesions in 64 rabbits, epileptic activity and gray matter edema were correlatively investigated during the initial phase (23 h). Indexes were developed to allow a quantitative assessment of epileptic activity. The indexes demonstrated that the early phase of cryogenic epilepsy is a very rapid phenomenon during the first 4 h postlesion. Epileptic activity precedes brain edema, and in individual animals, there is a significant positive correlation between the total amount of epileptic activity and the total amount of edema. The relationship between epileptic activity and brain edema are most likely interrelated at the level of pathophysiological mechanisms and several mechanisms can be postulated.

Animals↗
PubMedDate not supplied

Quinolinic-phosphoribosyl transferase activity is decreased in epileptic human brain tissue.

The presence of the excitotoxic and convulsant agent quinolinic acid (QUIN) in human brain has led to the hypothesis that an increase of this tryptophan metabolite could serve as an endogenous epileptogen. A possible mechanism for a pathological accumulation of QUIN being a deficiency in its degradation, we have measured the activity of quinolinic-phosphoribosyl transferase (QPRTase) (its first degradative enzyme) in stereo-EEG identified biopsies of human brain tissue. A specific reduction of QPRTase activity was observed in tissue primarily involved in the epileptic discharge compared to values from postmortem human brain tissue with no neurological disorders or nonpathological tissue from epileptic brains. A more severe decrease was noticed in the frontal and temporal cortices as compared to the amygdala or Ammon's horn. We suggest that this local deficit may contribute to the establishment or maintenance of an epileptic focus.

Adolescent↗
PubMedDate not supplied

[Measurement of flow in the Cordis-Hakin type ventricular shunt valve, used in the surveillance of hydrocephalic patients with shunts. An experimental study (author's transl)].

Using isotopes, Benabib et al. were able, in 1970 and following the work of Descuns et al., to evaluate the function of a ventricular shunt system be measuring the flow passing through it. The experimental study carried out confirmed the applicability of the method described by Benabib et al. to the Cordis-Hakim valve after substitution of the 131I used by those authors by 99mTc O4. Measurement of flow is valid only if true flow lies between 0.085 ml/mn and 1.7 ml/mn. Although with flow rates of less than 0.07 ml/mn the values obtained are overestimates, the distinction between no flow and slight flow remains definite.

Cerebrospinal Fluid↗
PubMedDate not supplied

[Method of automatic modal analysis of variations in intracranial pressure in man].

When ICP measurement is used for a neuro-surgical patient we wonder about two questions: --which are the highest and the mean ICP value? --is there some spontaneous pathological variations like plateau wave or b wave? To answer these questions it is necessary to record ICP for extended periods of time. Numerical values are difficult and tedious to set up from ICP standard recordings. To resolve this practical problem, JANNY and KULLBERG had proposed a statistical automatic analysis of the different ICP values using a computer. The modal curve of the different classes of ICP amplitudes is then recorded. For 62 patients with various pathological situations (head injury subarachnoid hemorrhage, posterior fossa tumor, normal pressure hydrocephalus and dementia with symetric ventricular enlargement...) ICP has been recorded during 12 hours at the same time on the standard ink-writer recorder, and on a standard multichannels automatical analysis giving the modal curve of ICP amplitudes. On the round-headed modal curve obtained, ICP modal value i.e. the most frequent pressure value, can be read directly. ICP variations beyond this modal value like plateau wave or vasomotor variations modify the general aspect of this modal curve and sometimes in a specifical manner as regarded to the pathological situation. In our findings posterior fossa tumor without high modal ICP level are frequent but in these cases vasomotor response are nevertheless always present. In cases of normal pressure hydrocephalus as defined by clinical aspect, ventriculography and cisternography, the ICP modal value is higher than 12 mm Hg and vasomotor variations like B wave occurs frequently. The most typical monophasic aspect has been noticed in cases of metastatic meningitis. This technical approach of ICP measurement is very useful and gives immediately to the clinician the exact mean or modal ICP value as measured on the modal curve of the different ICP amplitudes with more accuracy and attainability than on the usual long term recordings.

Brain Injuries↗