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Biomedical subjects

M Collard

Publications and source records attributed to M Collard.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

[Comparative study of changes in electroencephalographic and rheoencephalographic recordings with advancing age (author's transl)].

The correlation between the frequency index of the left parietotemporal E.E.G., and cerebral blood flow determined by rheoencephalography, was studied in 20 normal children (aged 8 to 13 years), 24 normal adults (18 to 45 years), 15 normal elderly subjects (78 to 95 years), and 37 patients with pathological disorders. A significant correlation was found in each group between the E.E.G. frequency index and blood flow rate. The occupation times correlating with the flow were: rapid rhythms in children, alpha rhythms (negative correlation) in normal adults, slow rhythms (negative correlations) in elderly subjects, and slow rhythms (negative correlation) in patients with pathological disorders.

Adolescent↗
PubMedDate not supplied

Ontogeny and homoplasy in the papionin monkey face.

Recent molecular research has provided a consistent estimate of phylogeny for the living papionin monkeys (Cercocebus, Lophocebus, Macaca, Mandrillus, Papio, and Theropithecus). This phylogeny differs from morphological phylogenies regarding the relationships of the mangabeys (Cercocebus and Lophocebus) and baboons (Mandrillus, Papio, and Theropithecus). Under the likely assumption that the molecular estimate is correct, the incongruence between the molecular and morphological data sets indicates that the latter include numerous homoplasies. Knowledge of how these homoplasies emerge through development is important for understanding the morphological evolution of the living papionins, and also for reconstructing the phylogenetic relationships and adaptations of their fossil relatives. Accordingly, we have used geometric morphometric techniques and the molecular phylogeny to investigate the ontogeny of a key area of morphological homoplasy in papionins, the face. Two analyses were carried out. The first compared allometric vectors of Cercocebus, Lophocebus, Macaca, Mandrillus, and Papioto determine which of the facial resemblances among the genera are homoplasic and which are plesiomorphic. The second analysis focused on early post-natal facial form in order to establish whether the facial homoplasies exhibited by the adult papionins are to some degree present early in the post-natal period or whether they develop only later in ontogeny. The results of our analyses go some way to resolving the debate over which papionin genera display homoplasic facial similarities. They strongly suggest that the homoplasic facial similarities are exhibited by Mandrillus and Papio and not by Cercocebus and Lophocebus, which share the putative primitive state with Macaca. Our results also indicate that Mandrillus and Papio achieve their homoplasic similarities in facial form not through simple extension of the ancestral allometric trajectory but through a combination of an extension of allometry into larger size ranges and a change in direction of allometry away from the ancestral trajectory. Thus, the face of Mandrillus is not simply a hypermorphic version of the face of its sister taxon, Cercocebus, and the face of Papio is not merely a scaled-up version of the face of its sister taxon, Lophocebus. Lastly, our results show that facial homoplasy is not restricted to adult papionins; it is also manifest in infant and juvenile papionins. This suggests that the homoplasic facial similarities between Mandrillus and Papio are unlikely to be a result of sexual selection.

Animals↗
PubMedDate not supplied

Comparative study of cerebral vasoactivity in vascular sclerosis of the brain in elderly men.

Thirty-five elderly patients underwent a systematic series of cerebrovascular examinations. The patients were divided into three groups on the basis of clinical criteria: normal patients (Group 1), patients with sequelae of a previous stroke or with minor mental disorders (Group 2), and patients with arteriosclerosis dementia (Group 3). The vasomotor reactions of the cerebral arteries were investigated by estimating regional cerebral blood flow (133Xe clearance technique). The authors emphasize the existence of cerebral vasoreactivity in subjects with clinical symptoms of senile dementia. Furthermore, in each of the three groups of elderly patients, there seemed to be a lack of correlation between the clinical symptoms and certain specific vascular examinations.

Age Factors↗
PubMedDate not supplied

[A new era in neuroradiology. Computerised axial transverse tomography-C.A.T.T. (Emi-Scanner) and its applications (author's transl)].

With an adequate follow-up, the authors report their experience with computerised axial transverse tomography (Emi-Scanner) after its use in 500 cases. A description of the method is followed by an account of the material used in this study. They mention the safety of C.A.T.T. and the profound change which this new technique has brought about in the chronology of neuroradiological investigations. The applications of C.A.T.T. are defined in relation to conventional neuroradiological investigations. In traumatic, degenerative, infective, neoplastic and vascular disorders, as well as epilepsy, C.A.T.T. makes possible visualisation of the lesion in the majority of cases. Having dealt with each of these indications, the authors illustrate the typical appearances seen at C.A.T.T. by significant examples. C.A.T.T. reduces the proportion of angiographic and encephalographic examinations. This tendency will become even more marked with the advent of technical development which improve the power of resolution of C.A.T.T.

Adult↗