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Biomedical subjects

P Buser

Publications and source records attributed to P Buser.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Long-term outcome after surgical closure of atrial septal defect in childhood with extensive assessment including MRI measurement of the ventricles.

Surgical closure of the secundum type of atrial septal defect (ASD) in childhood leads to excellent survival. However, relevant morbidity has been reported. Transcatheter closure of these defects has now become an alternative approach. To compare the results of the two different interventions, reliable data are needed on the long-term morbidity after defect closure with both methods. Patients were evaluated after a minimum of 10 years after surgical closure of an ASD in childhood. Assessment included analysis of perioperative data, interview, clinical examination, electrocardiogram, (ECG), 24-hour ECG, ergometry, chest radiograph, echocardiography, and MRI. A total of 66 patients underwent operation between 1971 and 1986 at our institution. Forty-eight of them (73%) were interviewed and 38 (58%) participated fully in the study program. Eighteen (27%) either refused to participate or were lost to follow-up. There were no substantial residual disorders, such as arrhythmias, right-sided heart dilatation, pulmonary hypertension, or reduced work capacity. Surgical closure of an ASD in childhood has an excellent long-term outcome. Surgical closure is thus the standard against which transcatheter closure needs to be measured.

Adolescent↗
PubMedDate not supplied

[Role of the amygdala in the occurence of oro-alimentary signs of during epileptic seizures in man (author's transl)].

The authors study the role of amygdala dysfunction in cases of oro-alimentary signs occuring in seizures recorded during a series of stereo-electroencephalographic investigations (S.E.E.G.) carried out for neurosurgical purposes. The patients under study have an epilepsy that is resistant to drug therapy. This work concerns 89 seizures with "oro-alimentary motor activity" recorded in 59 patients with whom it was possible to establish sufficiently rigourous anatomical - electrical - clinical correlations. This study enabled us to show that : --a seizure characterized by "oro-alimentary motor" signs (with the exclusion of swallowing movements) is related to a discharge that directly involves the amygdala. --a critical discharge affecting the anterior temporal region is expressed as : oro-alimentary activity either accompanied or not by other signs (breaking contact is exceptional). --late "oro-alimentary motor activity" also indicates disorganization of the amygdala, but offers no conclusion on the origin of the discharge.

Amygdala↗
PubMedDate not supplied

Unilateral paralytic strabismus in the adult cat induces plastic changes in interocular disparity along the visual midline: contribution of the corpus callosum.

Neurones activated through the corpus callosum (CC) in the cat visual cortex are known to be almost entirely located at the 17/18 border. They are orientation selective and display receptive fields (RFs) distributed along the central vertical meridian of the visual field ("visual midline"). Most of these cells are binocular, and many of them are activated both from the contralateral eye through the CC, and from the ipsilateral eye via the direct retino-geniculo-cortical (GC) pathway. These two pathways do not carry exactly the same information, leading to interocular disparity between pairs of RFs along the visual midline. Recently, we have demonstrated that a few weeks of unilateral paralytic strabismus surgically induced at adulthood does not alter the cortical distribution of these units but leads to a loss of their orientation selectivity and an increase of their RF size, mainly toward the ipsilateral hemifield when transcallosally activated (Watroba et al., 2001). To investigate interocular disparity, here we compared these RF changes to those occurring in the same neurones when activated through the ipsilateral direct GC route. The 17/18 transition zone and the bordering medial region within A17 were distinguished, as they display different interhemispheric connectivity. In these strabismics, some changes were noticed, but were basically identical in both recording zones. Ocular dominance was not altered, nor was the spatial distribution of the RFs with respect to the visual midline, nor the amplitude of position disparity between pairs of RFs. On the other hand, strabismus induced a loss of orientation selectivity regardless of whether neurones were activated directly or through the CC. Both types of RFs also widened, but in opposite directions with respect to the visual midline. This led to changes in incidences of the different types of position disparity. The overlap between pairs of RFs also increased. Based on these differences, we suggest that the contribution of the CC to binocular vision along the midline in the adult might be modulated through several intrinsic cortical mechanisms.

Action Potentials↗