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Biomedical subjects

G Guiot

Publications and source records attributed to G Guiot.

At least 19 recordsLinked to original sources

[Prolactin secreting adenomas: surgical treatment and results. 120 female cases, 30 males cases (author's transl)].

Twenty one per cent of the female cases concerned microadenomas discovered because of amenorrhea with or without galactorrhea. Sixty two per cent of these cases were cured by surgery alone, against 40% of the other types of prolactin (Prl) -- secreting tumors with extra-sellar extensions which were not cured. With men, no microadenomas was discovered (although one case demonstrated their possible existence) and in the most frequent cases, tumors exhibited extra-sellar extensions sometimes very large (giant tumors). In these cases, tumoral symptoms were cured by surgery while only 5 out of 30 men recovered a normal plasma Prl. level (30 ng/ml). In all cases the prognosis was established taking into account the volume and invasive characters (at the surgical and histopathological level) of the tumors. The different therapeutical approaches of these tumors (i.e. medical treatment by CB 154, surgery of Rxtherapy) were evaluated. Anyway the necessity of an earlier diagnosis is pointed out allowing the possibility of a selective adenomectomy by a microsurgical approach.

Adenoma

Thalamic spatial variability and the surgical results of lesions placed with neurophysiologic control.

One hundred stereotactic thalamotomies performed for upper extremity tremor were reviewed and the spatial positions of the anterior limit of ventralis posterior (VP), the thalamic-internal capsular boundary and somatotopic areas within VP plotted with respect to the midline and the place of the anterior comissure. Considerable variability was noted as to the location of these points. The surgical results following 97 of the 100 thalamotomies were evaluated at least three months after the procedure. Fifty-six of 70 patients with Parkinsonian tremor had complete abolition of their upper extremity tremor, as did 20 out of 27 patients with intention tremon. Plotting the spatial positions of the lesions in those cases in which the tremor was abolished and those cases in which tremor continued revealed little difference. However, in all of the cases in which upper extremity tremor was totally abolished, the lesion site was situated in ventralis lateralis anterior to the VP representation of the buccal commissure, thumb, or index finger. This study not only demonstrates the wide range of individual spatial variability in thalamic structures, and the necessity for neurophysiologic corroboration of radiologic information during stereotactic surgery if optimal results are to be obtained, but also suggests a somatotopic organization within ventralis lateralis.

Adolescent

Afterdischarges elicited by electrical thalamic stimulation in the hemicerebellectomized baboon.

Electrical stimulation of the ventrolateral (VL) nucleus of the thalamus was performed on hemicerebellectomized baboons. Stimulation was delivered in volleys of 40 to 60 Hz lasting 5 to 25 sec, and at intensities ranging from 1 to 6 mA (width of shock 0.5 to 5 msec). Similar parameters of stimulation produced asymmetrical motor and electrocortical responses. When the normal VL nucleus was stimulated, these responses were tonic or tonic-clonic. When the VL nucleus deprived of its cerebellar afferents was stimulated, the tonic-clonic responses were followed by afterdischarges appearing in the EEG which persisted after cessation of stimulation. The role of the cerebellum in the lowering of the excitability threshold of some structures, particularly the VL nucleus, is discussed, as are the systems likely to play a role in producing various clinical responses.

Animals

[10 cases of giant lumbo-sacral neurinoma].

Among giant tumours of the cauda equina, apart from ependymomas, neurinomas merit a special place. Depending on their site, they give rise to severe lumbar pain or root pain, with, almost constantly, aggravation during the night. X ray suggests the diagnosis when one finds displacement of the bone without inflammation, a regular bony defect, well-limited and asymmetric, and when the tumour is frequently prolonges in several directions across the bony orifices, sometimes giving a very large paravertebral mass which requires a double approach during surgery. The prognosis of isolated neurinomas is excellent, with disappearance of the pain immediately after operation, regression of the neurological signs or, at any rate, stabilisation when the latter are important. As far as the problem of spinal stability is concerned, this has been solved by sufficient spontaneous bony reconstruction.

Adolescent