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Biomedical subjects

M Poncet

Publications and source records attributed to M Poncet.

124 records · Page 7Linked to original sources
PubMedDate not supplied

Proportional localization system for anatomical interpretation of cerebral computed tomograms.

The existence of individual variations in size and shape of the human brain constitutes a problem for the anatomical interpretation of brain reconstructed images obtained from scanning devices; it is, for example, responsible for most of the inaccuracies in reading CT scans. One way to account for these variations is to use a proportional localization system. In the 1960s a group of neurosurgeons developed such a system based on two pivotal intracerebral structures, the anterior and the posterior commissures; they published an atlas consisting of horizontal, coronal, and sagittal brain sections interpreted in the proportional system. The atlas also included standard proportional brain schemes based on anatomical and radiological studies on large numbers of individuals. In this article we report a target localization experiment that we carried out to determine if this atlas could be used as a reference for a more accurate interpretation of CT and, eventually, of positron emission tomography (PET) and nuclear magnetic resonance (NMR) scans. Ten radiopaque small targets were inserted through the skull in the cortex of three cadavers; head CT was performed, and the atlas was used for predicting the cortical location of the targets seen on the CT images: The predictions were confirmed. These results strongly support the use of the proportional atlas for the interpretation of CT as well as of PET and NMR scans.

Anatomy, Artistic↗
PubMedDate not supplied

[Clinical trials in dermatology. Evaluation of the tolerability and efficacy of a topical anti-inflammatory treatment in atopic dermatitis].

Study designs for assessment of topical anti-inflammatory drugs in atopic dermatitis are discussed. Atopic dermatitis is a chronic disease with symmetrically distributed lesions. In order to avoid individual and spontaneous variation and to obtain an early impression of the efficacy of a new topical drug, bilaterally paired lesions can be used. Further drug development requires controlled double-blind parallel group design. General recommendations regarding inclusion criteria, and the measurement of efficacy and safety parameters are presented. Methods available for data evaluation and the particularities of different clinical designs are discussed.

Administration, Topical↗
PubMedDate not supplied

[Clinical trials in dermatology. Statistical support].

To determine the efficacy or safety of new topical treatments, more or less standardized studies must be performed. This article presents several examples of statistical analyses of the data currently seen in the dermatology area, and some guidelines for study sample size determination. More importantly, it indicates, for as soon as phase I studies, the need for preliminary informations such as development strategy, historical data, literature references or pilot studies, to determine or adapt appropriate designs and sample sizes. This need can be filled by close collaboration among clinicians, statisticians and sponsor.

Clinical Trials as Topic↗
PubMedDate not supplied

[Clinical trials in dermatology. Evaluation of the tolerability and efficacy of a topical anti-acne].

Acne is a frequent dermatologic disease of the teenagers. Methodology of antiacne preparations clinical trials has evolved recently, leading to better comprehension of acne treatment on acne lesions. The main rules for good clinical evaluation of acne treatments are: an objective counting of each individual lesions on a defined area (face, back), a global acne assessment, a therapy duration from 1 to 3 months or more, a skin safety evaluation for erythema, desquamation, dryness, itching, burning and oiliness with a 0 to 3 scoring system.

Acne Vulgaris↗
PubMedDate not supplied

[Stuporous state in an epileptic treated with sodium valproate. Diagnostic problems].

The authors report a case of stupor secondary to valproic acid, in a patient treated with this drug and phenobarbital for a complex partial form of epilepsy. The pathogeny of this rare complication is discussed. In this patient, a paradoxical epileptic reactivation is excluded, and the authors favor a metabolic mechanism: either hyperammoniemia or a perturbation in cerebral neuro-transmitter systems are proposed.

Adult↗
PubMedDate not supplied

[Athymhormic syndrome and progressive paraplegia disclosing adrenoleukomyeloneuropathy in an adult].

A 40-year-old man presented with both paraparesia and an athymhormic syndrome. Bicapsular lesions together with abnormal evoked motor potentials suggested cortical and spinal involvement in the deficiency syndrome. The neuropsychologic symptoms appeared to be secondary to bilateral pallidium lesions. Associated signs were adrenoleukocystrophy and adrenomyeloneuropathy suggesting the term, adrenoleukocyeloneuropathy.

Adrenoleukodystrophy↗
PubMedDate not supplied

[Isolated involvement of motivated behavior and basal ganglia diseases].

Focal brain lesions involving bilaterally either the globus pallidus, the corpus striatum or the deep frontal white matter, may result in a distinctive syndrome whereby patients become totally inert, with massive decrease in spontaneous behaviour, despite lack of obvious cognitive and mood disturbances. This syndrome has been variously labelled as "loss of psychic autoactivation" (Laplane et al.), "loss of action initiation and maintaining" (Ali Chérif et al.), "athymhormic syndrome" (Habib & Poncet). The most salient feature of this syndrome lies in the dissociation found between dramatic decrease in spontaneous mental (gestural, linguistic, emotional) productions, on the one hand, and almost normal productions given in response to external orders or stimulations, on the other hand. Patients are totally aware of these behavioural changes. According to their own reports, they do not suffer from these changes, they are not depressed or anxious, they do not make any plans or projects. Finally, a striking feature of their subjective experience is that they very often report an absence of spontaneous thought ("mental emptiness"). It is all though psychophysiological processes responsible for releasing and maintaining self-initiated behaviours or behaviours occurring in response to appetitive or aversive environmental stimulations, were impaired; this impairment may thus be termed a "motivational" disorder. Observations of the brain lesional substrate of this syndrome have focused on several sub-cortical neural structures, whose common feature is to be tightly connected with elements of the dopaminergic meso-limbic system, known from abundant experimental evidence to be chiefly involved in the regulation of motivated behaviour.

Basal Ganglia Diseases↗